Ministers order National Grid to explain blackout chaos

An apology for the "totally exceptional" rush-hour blackout in parts of London on Thursday night, which caused transport chaos and cost the economy millions, was issued yesterday by the National Grid.

Claims by the Mayor of London, Ken Livingstone, that the two-stage power failure in south London was a result of under-investment in the system were rejected, as were comparisons with the recent blackout on the east coast of the United States.

But the Grid, which is run by a private-sector company, must account to ministers for the failure. Stephen Timms, the Energy minister, ordered National Grid Transco to report back as soon as the exact problem had been found. He said: "We don't think there is any ground for complacency. What happened yesterday was deeply damaging and distressing for a very large number of people."

The blackout also provided the first real test of the capital's procedures, overhauled after the 11 September attacks, for dealing with terrorist attacks and other emergencies. The London Resilience Team, which co-ordinates the work of the emergency services and local and central government departments and is linked to Whitehall's Cobra crisis management operation, faced its biggest test since it was formed in October 2001.

Although the actual blackout lasted for only 30 minutes, the knock-on effects were severe. Most of the Underground system was closed until late in the evening and hundreds of commuters had to be led from stalled trains. All of London's southern rail terminuses, including Waterloo, Victoria and Charing Cross, and much of the network south of the Thames, were paralysed.

Hundreds of thousands of people suffered severe travel disruption, with overcrowded buses and taxis unable to cope. Many commuters had journeys home three or four times the normal duration. Many traffic lights were temporarily put out of order, and power was cut to large swaths of south London, affecting homes, businesses, shops and hospitals. But Scotland Yard said there had been no noticeable increase in crime, disorder or traffic incidents.

The National Grid said the blackout was caused by two incidents in parts of what is known as the 275KV South London Ring, a network of sub-stations distributing power to EDF Energy (formerly London Electricity) which supplies consumers direct. At 6.10pm a alarm went off in the Grid's London control room, which indicated the presence of gas in a transformer at a sub-station at Hurst in Kent. Engineers were dispatched to examine the problem and 10 minutes later the transformer was taken out of service. But, within seven seconds, as power was being moved around the system to compensate as part of normal back-up procedures, the underground power line between New Cross and Wimbledon in south London was switched off automatically, causing the blackout. The problem took 30 minutes to identify and fix and EDF Energy was able to restore full power to all areas 15 minutes after that.

The Grid said the first incident was a routine equipment fault, which would normally not have affected consumers, and the failure of the back-up system was causing most concern. Roger Urwin, the chief executive of National Grid Transco, said: "We wish to offer our sincere apologies to everyone. It was a very rare combination of events which had nothing to do with lack of investment or shortage of manpower.'' He said £300m a year was being invested in the system.

Mr Urwin said the cause of the faults was still being investigated and the inquiry would focus on whether they were coincidental or linked. There was "no sign of significant human error''.

Mr Timms later denied suggestions that the Government had failed to invest enough money into generating capacity. "There are questions about capacity but what happened was not about generating capacity, it was about a problem in the distribution network. The network failed and that is an entirely separate issue from generating capacity."

Mr Livingstone, who "saw the lights go out in east and south London" from his eighth-floor office, condemned the cuts as an "absolute outrage". He added: "You have to ask why it is a country which is the fourth richest in the world cannot invest enough in its power supply to maintain power.

"It is totally unacceptable that this has happened, affecting at least 250,000 people, as well as the transport system. Under-investment in the National Grid must not be allowed to cause this kind of chaos in a city like London. This event demands the fullest inquiry to ensure it does not happen again.''

Until last year, London Underground was immune to power failures on the National Grid, since it took its power from a station at Lots Road in Chelsea, but this was taken out of service in the privatisation programme. The Underground now relies upon three supply points from the Grid, one of which was affected by the blackout.

London's business community was also badly affected by the blackout, although many shops and businesses had already closed. Some restaurants, bars and pubs did better trade than expected from thousands who postponed their journeys home. Colin Stanbridge, chief executive of the London Chamber of Commerce, said the estimated cost of disruption would run into millions. "Having the Tube go down at the height of the rush hour is the very worst possible advertisement for London. It is an event of enormous concern to businesses across London."

Union leaders called for a reappraisal of the entire electricity network. National Grid was privatised in 1990 and last year made a profit of £667m.