Leander-class cruiser (1931)

During the war, significant modifications were made to the vessels. Various additional anti-aircraft armaments were added, and the two New Zealand vessels removed a turret to carry heavier 20 mm and 40 mm anti-aircraft guns in its place. Changes to the aircraft launching capability were reported, although use is unclear.

• Leander

Named after the character from Greek mythology. Loaned to New Zealand, commissioned as HMNZS Leander in September 1941. At the Battle of Kolombangara, Leander was heavily damaged by a Long Lance torpedo, causing many casualties, and sending the ship to repairs for two years.

• Achilles, later HMIS/INS Delhi.

Achilles was the second vessel loaned to New Zealand, commissioned as HMNZS Achilles in September 1941. She had earlier participated in the Battle of the River Plate. Achilles was sold to India in 1948, and was known as HMIS Delhi for a few years, then served as INS Delhi, until 1978.

• Ajax

Ajax participated in the Battle of the River Plate. The town of Ajax, Ontario was named after the ship, with street names in the town named after members of the crew. Ajax also participated in the Battle of Cape Matapan and took part in shelling the mainland of Normandy during the beach landings. Chile wanted to buy HMS Ajax in 1948-9, but the opposition leader in the UK, Winston Churchill thought the ship should be retained for the RN and it became a political issue.[3] The Leander class cruisers were very well built in the early 1930s and in the case of Achilles proved capable of more than 40 years service. After the rest of the class, including HMS Ajax, were scrapped, there was regret in the RN, because in many ways with their long 12,000-mile range and generous hull they were ideal for use as ocean radar pickets.[4]

• Neptune

Manned by New Zealand crew, although not part of the Royal New Zealand Navy. Neptune was sunk by an Italian mine off the coast of Tripoli.

• Orion

Orion spent much of the early war in the Mediterranean providing escort to convoys and was also at the Battle of Cape Matapan in March 1941. She participated in the evacuation of Crete in 1941 and was heavily damaged. Orion's repairs were completed in March 1942, after which she was widely employed, in home waters and on convoy escort duties to Africa and the Indian Ocean. Orion returned to the Mediterranean in October 1942 and was involved in convoy escort duties and supported the army in the invasion of Sicily. She also took part in the Normandy Landings in June 1944, where she fired the first shell. Orion received 13 battle honours, a record only exceeded by HMS Warspite and matched by two others.

The last three ships of the class, referred to as the "Modified Leander", "Amphion", or "Perth" class, had their machinery and propulsion equipment organised in two self-contained units (separated fore and aft), allowing the ship to continue operating if one set was damaged.[5] The two exhaust funnels, one for each machinery space, gave the modified ships a different profile from the early Leanders, which had a single funnel.[5] To cover the separate machinery spaces, the side armour was extended from 84 to 141 feet (26 to 43 m), negating the weight reduction created by the separation.[6] During design, it was planned to modify the forward-most and aft-most 6-inch turrets to be fitted with three guns instead of two, but the plan was cancelled when it was determined that the required alterations would cause several negative side effects, including reducing the ship's top speed and causing problems with effective fire control.[7] All three ships were sold to the RAN, Sydney while under construction and Perth and Hobart after a few years of British service.

• Perth (ex-Amphion)

Completed 1936 as HMS Amphion and transferred to the RAN as HMAS Perth in 1939. She operated with British ships in the Battle of the Mediterranean, participating in the Battle of Cape Matapan in March 1941. Lost in the Battle of Sunda Strait in early 1942.

• Hobart (ex-Apollo)

Completed 1936 as HMS Apollo and transferred to the RAN in 1938 as HMAS Hobart, she took part in the East African Campaign, the Battle of the Coral Sea and provided fire support at Guadalcanal. After being badly damaged by a torpedo strike in 1943, she returned to action in the Philippines landings (1944), followed by the Borneo and Aitape-Wewak campaigns. She was put into reserve after the war and was not decommissioned until 1962.

• Sydney (ex-Phaeton)

Laid down as HMS Phaeton, the ship was acquired by the RAN, launched as HMAS Sydney and was commissioned in 1935. Also involved in the Mediterranean campaign. Sydney sank the Italian cruiser Bartolomeo Colleoni at the Battle of Cape Spada in 1940. Later that year, Sydney took part in the Battle of Cape Matapan and Battle of Calabria, sinking two Italian destroyers, the Espero and Zeffiro. In 1941, off Western Australia, Sydney encountered the German auxiliary cruiser Kormoran; the two ships destroyed each other and Sydney was lost with all hands; the wrecks of both ships were located in 2008.