2003 London blackout

Even before the blackout, the UK press were anticipating a UK equivalent of the Northeast blackout of 2003 in North America, which occurred two weeks earlier (August 14) and affected about 100 times more people. For example, on August 15, The Daily Express had reported that the National Grid might not be able to cope with predicted power surges within the winter of 2004.

On the day of the blackout the BBC reported major problems on transport including the London Underground.[2]

Headlines such as "Power cut cripples London" (CNN) concealed the fact that over 90% of London's population was unaffected (but see below for the effects on the London Underground and mainline rail services).[3]

Later it became clear to the press that the blackout might not be directly attributable to underinvestment, but this was still the main thrust of the stories: e.g. The Independent, 30 August: "Just admit it, Mr Urwin. National Grid needs to invest more". [4]

On 8 September the London Evening Standard ran a story "Blackout report will take weeks".[5] On 10 September National Grid published a 43-page report describing the causes of the blackout (and made it available on the internet). The national BBC TV evening news did not cover this.

In mid-October an anonymous National Grid engineer spoke to the BBC. It emerged that there may have been a maintenance problem not covered in National Grid's report (see below).

Initial reports were that there appeared to be a problem with a cable feed from the national grid in the Wimbledon area of south London. A spokesman for National Grid said it was "an unusual occurrence", but "not even vaguely on the scale of what happened in the U.S.", adding that there was a fault in the 275 kV system.

Later National Grid's report revealed that the second fault, and the ultimate cause of the blackout, was the fitting of a wrongly rated part in a backup system - a Buchholz protection relay had the wrong setting; similar to fitting a 1 ampere fuse instead of a 5 ampere fuse. The first fault was a problem with a different transformer. The impression was given that this first fault was in a sense routine - about 13 such faults happen in a year. Normally it would be possible to switch the transformer that faulted first, out of the system and continue with power uninterrupted using spare capacity on the adjacent second transformer, also in Wimbledon, but in this case the switch over exposed the human error in using a part with the wrong setting on the second transformer.

On 17 October it emerged that the first transformer fault was due to an oil leak, spotted some weeks before the blackout. The oil had been topped up but the leak had not been cured. National Grid's Director Of Transmission admitted to a "small backlog" of maintenance checks. [6]

The London Fire Brigade took around 400 calls and made 100 rescues of people stuck in lifts. All main rail services were at a standstill in south London and the south-east. Sixty percent of the London Underground was affected [2] (London Underground had shut down the last of their independent generators in favour of using Grid supplies in 2002) and people were stuck underground. 270 sets of traffic lights were hit. To relieve the transport problems, buses accepted train and Tube tickets. Thousands of people took to the rain-soaked streets. Pubs filled up with people sitting out the delays.

• List of power outages
• Brittle Power