McDonnell Douglas Phantom in UK service

The British Government ordered four prototypes (two F-4K and two F-4M), together with a pair of pre-production F-4K aircraft. The first UK Phantom, a prototype F-4K (designated YF-4K), first flew on 27 June 1966 at the McDonnell plant in St. Louis. The second made its first flight on 30 August 1966. The two pre-production F-4K aircraft were constructed alongside the prototypes, and were initially used for fit check trials of the various systems to be fitted. The first was used for catapult/arrestor and deck landing trials, and the second was primarily for testing the radar and missile systems. All four were delivered to the UK from 1969 to 1970 for continued test work by the Aeroplane and Armament Experimental Establishment (A&AEE), Ministry of Defence Procurement Executive, Rolls-Royce and BAC (and later its successor, British Aerospace).[23][24] The first F-4M prototype (designated YF-4M) first flew on 17 February 1967, and was also used for fit checks before delivery to the UK.[25]

In 1964, the Phantom was ordered for the FAA to serve as the Royal Navy's primary fleet air defence aircraft, with a secondary strike capability. It was intended that these aircraft would operate from the decks of four aircraft carriers; Eagle and Ark Royal, which would be rebuilt to enable the operation of the aircraft,[29][lower-roman 2] and two planned new ships.[lower-roman 3][33]

A US Navy Phantom performs a touch-and-go landing aboard HMS Hermes. Only Eagle and Ark Royal were big enough to operate the Phantom successfully.[16]

The heat from the Spey's afterburners required the installation of special water-cooled jet blast deflectors aboard Ark Royal to avoid extensive damage to the flight deck.[37]

The requirements for the intended force of four carriers meant that five squadrons of Phantoms would be needed.[22] However, in its 1966 Defence White Paper, the Government decided to cancel the two new carriers, which led to a reduction in the total order from 140 to just 48, with options for another seven.[38] The intention was to form a pair of front-line squadrons, each of twelve aircraft, that would operate from the two remaining, heavily modernised fleet carriers. The remaining 24 aircraft were to be used to form a training unit, and to provide a reserve pool in the event of aircraft losses.[31]

The Royal Navy received its first F-4K Phantoms, which carried the British designation FG.1, in April 1968.[39] These were assigned to 700P Naval Air Squadron (NAS), which was to serve as the Intensive Flying Trials Unit. Upon completion of the successful flight trials, 767 Naval Air Squadron was commissioned in January 1969 as the FAA's training squadron. This was followed at the end of March 1969 by 892 Naval Air Squadron, which was commissioned as the Royal Navy's first operational Phantom unit.[40][41] During 892 NAS's initial work up, three of its aircraft were entered in the Daily Mail Trans-Atlantic Air Race, a competition to commemorate the 50th anniversary of the first trans-Atlantic flight.[42] One aircraft set a record of four hours and 46 minutes for the west to east crossing between Floyd Bennett Field in New York City and Wisley Airfield outside London, a record that stood for five years.[43][44]

At the same time as the FAA was receiving its first aircraft, the A&AEE had three FG.1s delivered to its 'C' Squadron for flight deck trials aboard Eagle. Two sets of trials were successfully carried out in March and June 1969; the first comprised approaches and touch-and-go landings,[45] while the second set of trials involved full catapult launch and arrested recovery.[46] As a result of the reheat from the Spey turbofans, the ship's jet blast deflectors (JBD) were not used; instead a steel plate was fixed to the deck to absorb the heat of the engines building to launch, and fire hoses were used after each launch to prevent them melting.[47]

Ark Royal had entered refit to accommodate the Phantom in 1967; this involved a major reconstruction, including several elements to allow the ship to operate the aircraft – the flight deck was increased in area and fully angled to 8½°, the arresting gear was replaced with a new water-spray system[48] to accommodate the Phantom's higher weight and landing speed, and bridle catchers[lower-roman 4] and water-cooled JBDs[lower-roman 5] were fitted to the catapults.[37] Once this work was complete, Eagle was scheduled to undergo a similar modernisation. However, the planned phasing-out of fixed-wing aviation in the Royal Navy led to the intended refit of Eagle being cancelled, with the options for seven additional FG.1s not taken up.[27] As a consequence, it was decided to further reduce the FAA's Phantom fleet to just 28 aircraft.[38]

In 1970, Ark Royal embarked 892 NAS as part of her air group for the first time, with a total of 12 aircraft. The first operational use of the Royal Navy's Phantoms had come in 1969, when 892 NAS had embarked for training with the US aircraft carrier USS Saratoga in the Mediterranean, and had undertaken air defence missions alongside the ship's own F-4Js.[49] This deployment showed the necessity for the modifications fitted to Ark Royal. During the initial launches from Saratoga, the heat from the afterburners, combined with the increased angle of attack resulting from the extendable nosewheel, caused the deck plates to distort, leading to subsequent catapult launches being undertaken at reduced weight without the use of re-heat.[30]

During Ark Royal's first three-year commission, 892 NAS, which had initially used RNAS Yeovilton in Somerset as its home base, moved to RAF Leuchars in Fife where, during the periods when it was not embarked, it undertook Quick Reaction Alert (QRA) duties alongside the RAF's 43 Squadron. At the same time, 767 NAS was disbanded as the Royal Navy's Phantom training unit - the squadron had been the joint training unit for both the FAA and the RAF in using the FG.1. In its place, an RAF-operated Phantom Training Flight was established at RAF Leuchars in August 1972.[50][51]

The Phantom served in the FAA until 1978, when Ark Royal was withdrawn from service, leaving no ship in the Royal Navy capable of operating the type. The final catapult launch from Ark Royal was a Phantom of 892 NAS on 27 November 1978 during the disembarkation of the air group;[52] the squadron's aircraft were delivered to RAF St Athan in Wales, where they were handed over to the RAF.[53] During the type's service with the Royal Navy, 10 of the total FAA fleet of 28 were lost in crashes.[54]

The Phantom had significant advantages over the Lightning as an interceptor in terms of range, avionics and weapons fit.[55]

Following the cancellation of the planned refit of HMS Eagle to allow her to operate the Phantom, a total of 20 airframes that had originally been ordered for the FAA were diverted to the RAF to serve in the air defence role.[28] At the time, the RAF's primary interceptor was the English Electric Lightning, which had comparatively poor range, loiter time and weapons fit. These limitations hampered its effectiveness, especially in long interceptions of Soviet Air Forces and Soviet Naval Aviation bombers and reconnaissance aircraft over the North Sea and North Atlantic. A new Phantom squadron was formed at RAF Leuchars,[50] the UK's most northerly air defence base at the time, to take advantage of the improvements that the Phantom provided over the Lightning – it could carry more fuel, and had consequently better range and endurance; it was fitted with a more powerful radar; and it could carry more missiles (up to 8, compared to 2 for the Lightning).[lower-roman 6] On 1 September 1969, 43 Squadron was formed at Leuchars, operating as part of the UK's northern QRA zone alongside the Lightnings of 11 Squadron and 23 Squadron. In 1972, when 11 Squadron was redeployed to join 5 Squadron at RAF Binbrook, it was replaced at Leuchars by the Royal Navy Phantoms of 892 NAS.[41][56]

Upon the withdrawal of HMS Ark Royal in 1978, the Phantoms of the FAA were handed over to the RAF and used to form a second squadron at Leuchars. At the time, 111 Squadron was stationed there operating the FGR.2 version of the Phantom, having been there since 1975.[57] In 1979, to save costs resulting from the differences between the FG.1 and FGR.2, the squadron converted to the ex-Navy aircraft and the FGR.2 airframes were distributed to other Phantom units. Upon 111 Squadron's conversion to the FG.1, the Phantom Training Flight, which had been resident at Leuchars since 1972, was disbanded, and responsibility for all Phantom conversion training turned over to 228 Operational Conversion Unit.[50]

Both 43 and 111 Squadrons retained the FG.1 until 1989, when they converted to the new Tornado F.3. Following the standing down of the two operational squadrons and the final withdrawal of the type from service, the bulk of the RAF's FG.1 Phantoms were scrapped.[58][59] The RAF lost eight of their FG.1s in crashes throughout the type's twenty year service.[54]

•  United Kingdom
  • Aeroplane and Armament Experimental Establishment[60]
•  Royal Navy[41]
  • 700P Naval Air Squadron
  • 767 Naval Air Squadron
  • 892 Naval Air Squadron
•  Royal Air Force[50]
  • No. 43 Squadron
  • No. 64 (R) Squadron
  • No. 111 Squadron
  • Phantom Training Flight

Following the cancellation of both the TSR-2 and P.1154 programmes, the RAF was still left with a requirement for aircraft in the long-range strike, close air support and reconnaissance roles. This resulted in orders for two aircraft types, the General Dynamics F-111K, intended for the long-range interdiction role, and the F-4M Phantom, which would be used for close air support; both aircraft were to be fitted for reconnaissance.[61][62] The F-111K was cancelled within a year of being ordered, but the order for 150 Phantoms went ahead alongside the Phantom order for the Royal Navy; the final 32 units of the RAF order were eventually cancelled.[63] The RAF Phantom, given the designation FGR.2, was broadly similar to the naval version, with some minor variations in terms of engines, avionics and structure, relating to its use as a land-based, rather than carrier-based aircraft.[64]

The first RAF Phantom unit was 228 Operational Conversion Unit, which was stood up in August 1968.[50] The Phantom entered operational service as part of Strike Command in May 1969, when 6 Squadron was formed at RAF Coningsby in the tactical strike role. 54 Squadron was formed in September the same year, followed by 41 Squadron in 1972 as a tactical reconnaissance unit. A further four squadrons were formed under RAF Germany in 1970 and 1971: 2, 14, 17 and 31 Squadrons, all at RAF Brüggen.[50]

Along with their conventional strike role, 14, 17 and 31 Squadrons were assigned a tactical nuclear strike role by SACEUR, using weapons supplied by the United States.[65][66] After initial work-up, 2 Squadron operated from RAF Laarbruch in the tactical reconnaissance role. The aircraft assigned to the two tactical reconnaissance units were fitted with a pod containing four optical cameras, an infrared linescan and a sideways looking radar.[67]

During the 1970s, France and the UK were developing a new aircraft which could fill the RAF tactical strike and reconnaissance missions: the SEPECAT Jaguar was introduced into service in 1974, and led to a re-think of the Phantom's role as, at the same time, the limitations of the Lightning as an interceptor were becoming more apparent. The conversion of the RAF's FGR.2 squadrons to operate the Jaguar, combined with its use of the Blackburn Buccaneer, meant that it was possible to begin transferring Phantoms to operate purely as interceptors in the air defence role.[50]

In October 1974, 111 Squadron converted from the Lightning to the Phantom FGR.2, becoming the first unit to operate the type in the air defence role (notwithstanding 43 Squadron, which had used the FG.1 version since 1969). As more Jaguars were delivered, more Phantoms were released enabling existing Lightning squadrons to be converted;[68] 19 Squadron and 92 Squadron, the forward deployed air defence units in Germany, converted in 1976 and 1977 respectively, at the same time moving from RAF Gütersloh, which was the closest RAF base to the East German border, to RAF Wildenrath, taking advantage of the Phantom's superior range over the Lightning.[22] Three further UK based squadrons, 23, 29 and 56, were also converted between 1974 and 1976.[22] 111 Squadron, which had been the first unit to use the FGR.2 as an interceptor, converted to the FG.1 version in 1979 following the transfer of the Royal Navy's remaining airframes to the RAF.[50] The Phantom subsequently served as the RAF's primary interceptor for over a decade until the introduction into service of the Panavia Tornado F.3 in 1987.[69][70]

Initially delivered to air defence units in green-grey camouflage (top), the RAF later adopted a pale grey colour scheme for its Phantoms (bottom).[71][72]

When Phantoms were first delivered to interceptor squadrons, they remained in the grey-green camouflage colour scheme more associated with the strike and close air support missions they had undertaken. During the late 1970s, the RAF began experimenting with new colours for its air defence units, with 56 Squadron tasked with trialling proposed new schemes. In October 1978, a Phantom FGR.2 of 56 Squadron became the first to be painted in the new air superiority grey colour, combined with small, low visibility roundels and markings. However, although the roundel remained in low visibility colours, individual squadron markings eventually returned to more observable sizes and colours.[71][72]

In May 1982, three Phantoms from 29 Squadron were forward deployed to RAF Wideawake on Ascension Island to provide air cover for the RAF's operations during the Falklands War, replacing Harriers of 1 Squadron, which were transiting to the war zone.[73] In October 1982, following the end of the conflict and the reconstruction of the runway, 29 Squadron detached nine of its aircraft to RAF Stanley to provide air defence for the Falkland Islands.[74] In March 1983 23 Squadron took up the role, remaining stationed there until October 1988, when they were replaced by 1435 Flight. To make up for the loss of an entire squadron from the UK Air Defence Region, the RAF procured 15 ex-USN F-4J Phantoms. These aircraft were operated by 74 Squadron from 1984 until 1991, when they were replaced by FGR.2 Phantoms that had been released by other squadrons following their conversion to the Tornado.[75]

Initially, it was intended that Phantoms and Tornados would serve alongside each other. A total of 152 Tornado F.3s were ordered for the RAF, enough to convert four squadrons of Phantoms and two of Lightnings, but insufficient to completely convert every air defence squadron. Both 23 and 29 Squadrons converted from the Phantom FGR.2 to the Tornado between 1987 and 1988, alongside the conversion of the final two remaining Lightning squadrons. The intention was to retain a pair of UK based Phantom squadrons at RAF Wattisham, alongside a pair of Tornado units at RAF Coningsby to provide air defence cover for the southern half of the UK Air Defence Region.[76] Another two squadrons stationed in Germany would also be retained.[77][78]

However the end of the Cold War saw the Phantom withdrawn from service under the Options for Change defence review. This saw the disbanding of 228 Operational Conversion Unit in January 1991, with the Phantom Training Flight, which had previously operated FG.1 training between 1972 and 1978, re-established for twelve months to run refresher courses on the type.[50] As part of the gradual run down of the RAF's presence in Germany, the two forward based units were to be disbanded, while there would also be a reduction in the number of air defence squadrons leading to the two UK based units being disbanded in late 1992.[79][75] However, just prior to the final withdrawal of the Phantom, it was recalled operationally as a result of Operation Granby, the UK's participation in the First Gulf War, when aircraft from 19 and 92 Squadrons were forward deployed to provide air defence cover at RAF Akrotiri; this was to replace the Tornados that had been originally deployed there on exercise, and were subsequently sent to the Gulf region.[80] Following their final withdrawal from service, with a few exceptions, the bulk of the RAF's FGR.2 fleet was scrapped.[59] Over its service life, 37 FGR.2s were lost to crashes.[54]

•  Royal Air Force[50]

F-4J(UK) Phantom F.3
A Royal Air Force Phantom F.3 of 74 Squadron in 1984.
Role	Air defence interceptor
National origin	United States
Manufacturer	McDonnell Douglas
First flight	10 August 1984
Introduction	19 October 1984
Retired	31 January 1991
Status	Withdrawn
Primary user	Royal Air Force
Produced	1984
Number built	15
Career
Serial	ZE350 – ZE364[82]

After the Falklands War, the UK government began upgrading the defences of the Falkland Islands to guard against any further aggression from Argentina. One of the measures taken was the deployment of 9 FGR2’s from 29 Squadron to RAF Stanley in October 1982, 23 Squadron taking the aircraft over in March 1983.[83] The removal of a squadron of Phantoms to the Falkland Islands left a gap in the UK's air defences and nothing immediately available to fill it. As a result, the UK government decided to purchase another squadron of Phantoms.[84]

Because the aircraft in RAF service were a special production batch built to UK specifications, it would not be possible to obtain identical aircraft, so 15 airframes were procured from among the best of the ex-USN F-4Js stored at the Aerospace Maintenance and Regeneration Center at Davis–Monthan Air Force Base in Arizona.[84] The F-4J was chosen because it was the variant from which the RAF's F-4Ks and F-4Ms were developed, and was thus the closest available to the British aircraft. The 15 that were selected were extensively refurbished at the Naval Air Rework Facility at NAS North Island and brought to a standard almost equivalent to the F-4S, which was the last variant in service with the USN, the only differences being the absence of leading-edge slats and a helmet gun sight.[84][85]

The major difference between the F-4J and the British Phantoms was the absence of the Rolls-Royce Spey turbofan, the former being fitted with the General Electric J79-10B turbojet. This produced less power than the British engine, but had a faster afterburner light up, giving it better performance at high altitude, at the expense of slightly poorer acceleration at low level. The high-altitude performance was helped by the reduced drag from its smaller air intakes.[84] Initially capable of carrying the AIM-7 Sparrow and AIM-9 Sidewinder air-to-air missiles (AAM), they were soon made compatible with the Skyflash and SUU-23A gun pod, bringing them into line with the rest of the RAF's Phantoms.[84] Despite modifications to allow them to operate with the rest of the fleet, the F-4Js retained the vast bulk of the equipment they were originally fitted with, even requiring their crews to use American flying helmets.[22]

Although the new Phantoms were assigned a British designation as the F.3,[86][87] they were generally referred to as the F-4J(UK).[38][88] They were assigned to 74 Squadron at RAF Wattisham, which stood up in October 1984, two months after the first flight.[50] The aircraft remained in service through the transition to the Tornado, which began entering service in 1987. In 1990, thanks to the conversion of F-4M squadrons to the Tornado, the RAF were able to transfer the best of its remaining FGR.2s to 74 Squadron, which meant that the F.3 was able to be withdrawn in January 1991.[75] With a couple of exceptions, all of the RAF's F-4Js were broken up for scrap.[59] One of the 15 airframes was lost in a crash in 1987, killing both crew members.[54]

•  Royal Air Force[50]
  • No. 74 Squadron

RAF Phantom FG.1 with SUU-23/A gun pod

The Phantom FG.1 and FGR.2 as built were similar, being fitted with broadly the same engines and avionics, although there were minor differences. The FG.1 was initially fitted with the Mark 201 version of the Rolls-Royce Spey turbofan, while the FGR.2 had the Mark 202; the Mark 201 had a degree of lag between throttle selection and engine response, which was remedied in the 202. The 201 was eventually upgraded to the Mark 203 version, which had a modified control system for the afterburner, allowing it to light faster and enable power to be applied quickly in the event of a bolter on the small decks of the Royal Navy's aircraft carriers.[89][18] Both variants were fitted with a licence built version of the Westinghouse AN/AWG-10 avionics package; the FG.1 was fitted with the AN/AWG-11, which differed primarily in having a nose radome that was hinged and able to fold backwards against the aircraft's fuselage to allow for storage in the hangar of an aircraft carrier;[lower-roman 8] the system was designed to be integrated with both the AGM-12 Bullpup missile and WE.177 free-fall nuclear weapon as required. The AN/AWG-12 fitted to the FGR.2 was not foldable, and featured a better ground mapping mode, to take into account the strike role for which the type was originally procured; allied to this was a Ferranti inertial navigation/attack system (removed when the type converted to the air defence role).[22] It was also configured to be able to control the SUU-23/A gun pod; FG.1s used by the RAF were also able to use the gun pod, but the Royal Navy's FG.1s lacked this capability.[92][93]

F-4K alongside an F-4J of the US Navy. This shows the extended nosewheel oleo of the British aircraft, fitted to increase the take-off attitude for operation on the Royal Navy's carriers.[94]

Although there were minor differences between the two types of Phantom built for the UK, there were many significant ones between the British Phantoms and those built for the United States. The most obvious was the substitution of the Rolls-Royce Spey turbofan for the General Electric J79 turbojet. The Spey was shorter but wider than the J79, which meant that the British Phantoms' intakes had to be redesigned for a higher airflow, making them 20% larger (with a consequent increase in drag), while the fuselage was widened by 152 mm (6.0 in). The position of the afterburner also meant that the rear of the fuselage had to be made deeper.[95] Auxiliary intake doors were fitted on the rear fuselage.[96]

Performance estimates of the British Phantom compared to its American equivalent indicated that the former had a 30% shorter take-off distance, 20% faster climb to altitude, higher top speed and longer range.[95] The Spey was more efficient at lower altitudes, and had better acceleration at low speed, giving British Phantoms better range and acceleration, which was shown during the deployment of 892 NAS to the Mediterranean aboard USS Saratoga in 1969, when the F-4K was repeatedly quicker off the deck than the F-4J used by the Americans.[97] It was less efficient at higher altitudes, the British Phantoms lacking speed compared to J79-powered versions owing to the increased drag of the re-designed fuselage.[18][95] This discrepancy became apparent when the F-4J was obtained by the UK in 1984; it was regarded as being the best of the three variants to serve in the RAF.[85]

The small size of the aircraft carriers Eagle and Ark Royal, from which the Royal Navy's Phantoms were intended to operate, compared to the USN carriers of the period, meant that the F-4K version required significant structural changes compared to the F-4J, from which it was descended, and which performed a similar role. As well as the folding nose radome to allow for storage in the smaller hangars of the British ships, it had to have a significantly strengthened undercarriage to account for the higher landing weight (British policy was to bring back unused ordnance). The F-4J featured a nosewheel oleo that extended by 20 inches (51 cm) to provide the correct attitude for launch from American catapults.[94] The F-4K's nosewheel oleo extended by 40 inches (100 cm) to increase the take-off attitude (the extension of the nosewheel put the Phantom at a 9° attitude[98]) due to the shorter and less powerful British catapults. It was also fitted with drooping ailerons, enlarged leading edge flaps and a slotted tailplane, and increased flap and leading edge blowing, all to improve the lift and handling characteristics of operation from the much smaller carriers of the Royal Navy.[30][lower-roman 6]

As the Phantom continued in service, other changes were made, most notably the Marconi ARI.18228 Radar Warning Receiver (RWR) fitted on top of the vertical stabiliser of FG.1 and FGR.2 Phantoms in the mid-1970s, but not to the F.3.[99] From 1978, the Skyflash AAM, derived from the AIM-7 Sparrow, began to be delivered to RAF Phantom units, and was used concurrently with the Sparrow; all three UK Phantom variants were eventually fitted to operate the Skyflash.[92]

• UK versions compared[lower-roman 6]
• 
  FG.1; 40 cm telescopic nosewheel oleo; hinged nose radome; wider and shorter engine exhausts; bigger air intakes; deeper rear fuselage; RWR installation on tailfin
• 
  FGR.2; no telescopic nosewheel; fixed nose radome; wider and shorter engine exhausts; bigger air intakes; deeper rear fuselage; RWR installation on tailfin
• 
  F.3; 20 cm telescopic nosewheel oleo; fixed nose radome; narrower and longer exhausts; narrower air intakes; shallower rear fuselage; no RWR installation on tail

The first batch of Phantoms produced for the UK received serials in the XT range, with a total of 44 production models (20 FG.1s and 24 FGR.2s), as well as the four prototypes and two pre-production models being given XT serial numbers.[26] The bulk of the UK's specially built Phantoms were delivered with XV serials (94 FGR.2s and 28 FG.1s), while the two cancelled sets of airframes (32 FGR.2 and 7 FG.1) also received XV numbers.[27] The second-hand examples (15 F.3) obtained in 1984 received serials in the ZE range.[82]

The RAF operated the Phantom from a number of bases in the UK, Germany and the Falkland Islands during its operational service, while the Royal Navy initially based its Phantom units at its main air station at Yeovilton; following the disbanding of the FAA's dedicated training squadron, its sole operational Phantom squadron was subsequently moved to take up residence at the RAF's base at Leuchars.[100][51]

Bases utilised by Royal Navy and Royal Air Force Phantom squadrons[41][50]
Base	Years used	Number of squadrons[lower-roman 6]
Phantom bases in the UK
RNAS Yeovilton	Apr 1968 - Sep 1972	3 × RN squadrons	RAF Leuchars RNAS Yeovilton RAF Wattisham RAF Coningsby
RAF Leuchars	Sep 1969 - Jan 1990	1 × RN squadron
		3 × RAF squadrons
		1 × RAF flight
RAF Coningsby	May 1969 - Apr 1987	5 × RAF squadrons
RAF Wattisham	Nov 1975 - Sep 1992	3 × RAF squadrons
		1 × RAF flight
Phantom bases in Germany (map displays North Rhine-Westphalia)
RAF Laarbruch	Dec 1970 - Feb 1976	1 × RAF squadron	RAF Brüggen RAF Laarbruch RAF Wildenrath
RAF Brüggen	Jun 1970 - Jun 1976	3 × RAF squadrons
RAF Wildenrath	Dec 1976 - Jan 1992	2 × RAF squadrons
Phantom bases in the Falkland Islands
RAF Stanley	Oct 1982 - May 1985	2 × RAF squadrons	RAF Stanley RAF Mount Pleasant
RAF Mount Pleasant	May 1985 - Jun 1992	1 × RAF squadron
		1 × RAF flight

Although the Phantom was ordered in 1966, the variants that were eventually constructed were not the first to be offered to the UK. McDonnell Aircraft had been conducting studies into the possibility of the Royal Navy using the Phantom on its carriers since 1959.

McDonnell concluded that more power was needed than the J79 turbojet could provide to operate from the smaller decks of British carriers and as a result consulted Rolls-Royce about whether the RB-168 Spey turbofan, then in development for use in the Blackburn Buccaneer, could be fitted to the aircraft.[101] In 1960, McDonnell approached the RAF with its model number 98CJ, which was an F4H-1 (later F-4B) with various modifications, including the installation of the Spey Mk.101 turbofan.[102] McDonnell continued studies, proposing afterburning Mk.101 engines in 1962, while trials of an F-4B fitted with an extendable nosewheel oleo took place aboard USS Forrestal in 1963.[101] In 1964, the company proposed the model 98FC, which was identical to the F-4D variant but would have been fitted with the RB.168-25R.[103]

A further proposal came after the order for the F-4M was being finalised, and was a result of the UK's need for an aircraft to perform the tactical reconnaissance role. For this, McDonnell offered two options:[104]

• The standard F-4M fitted with a reconnaissance pod in place of the centreline fuel tank
• A modified airframe, designated as RF-4M, with the reconnaissance equipment carried internally

Although the RF-4M would have had some advantages, it was discounted as the cost would have been greater, with consequently fewer aircraft purchased, while only those that had been modified would have been able to undertake the reconnaissance mission. Ultimately, the RAF chose the standard F-4M and external pod, which allowed all of its aircraft to perform all designated roles.[62]

Another McDonnell proposal was a variation of the carrier-based Phantom, with the goal of improving catapult performance and lowering approach speeds. The F-4(HL), also known as Model 98HL, was planned as a Spey-powered aircraft with a longer fuselage and wingspan, less sweep, stabilators with increased area and air intakes with auxiliary blow-in doors to increase airflow at low speeds. This proposal was not taken forward.[105][106]

Sir Sydney Camm, the Chief Designer at Hawker for many years, once said that no British aircraft could be considered a success until it was able to match the capabilities of the Phantom.[22] In the RAF and Royal Navy, it was the direct replacement in squadron service for a total of four different aircraft types, comprising nine separate variants. In turn, the Phantom was replaced in squadron service by three different aircraft (see table):