The UK could be hit by electricity supply problems within two years, an expert who advises the government on energy policy has said.
The UK is increasingly reliant on imported gas for electricity
Dieter Helm told BBC Two's 'If... The Lights Go Out' the UK had a "clapped out" power generation system and was too dependent on imported gas.
A committee of MPs has also warned of possible problems with the network.
But the Department of Trade & Industry said new capacity was being created by reopening mothballed power stations.
Government policy was focused on the safe, secure and affordable supply of electricity, the DTI said.
Mr Helm's concerns have been echoed the cross-party Trade and Industry Committee, which said much of Britain's power network was nearing the end of its 40-year lifespan.
"There is a danger that there is currently insufficient investment in the network to replace in a planned and orderly way equipment which is reaching the end of its life," the report said.
GAS SUPPLY NETWORK
"Simply to maintain present performance levels, capital
expenditure by the network owners would have to double," it said.
London and Birmingham both suffered power blackouts within the space of a week last summer, raising questions about the UK system's reliability.
The BBC's 'If... The Lights Go Out' programme asks if the UK is becoming too reliant on imported gas supplies and examines what could happen should terrorists attack a vital pipeline.
Luck running out?
Gas consumption in the UK has soared by 66% since 1992 to 113bn cubic metres a year, according to figures from industry regulator Ofgem.
Meanwhile, electricity generation using gas has jumped from just 1.7% of total consumption in 1990 to 29.7% in 2002.
Mr Helm accuses the government of having no insurance against power cuts.
GAS IMPORTS BY PIPELINE, 2002
UK: 4.7 bcm, of which:
3.6 bcm from Norway
1.1 bcm from the Netherlands
Germany: 81.7 bcm
Italy: 52.5 bcm
France: 32.7 bcm
bcm: billion cubic metres
He highlights the decline of North Sea gas and the condition of the UK's power stations as causes for concern.
The UK's coal power stations are due for replacement and most nuclear generators are set to close in the next decade.
Mr Helm says that without new policy initiatives the UK's luck will run out and there could be supply problems by 2006.
Defending its strategy, the DTI pointed out that the government had a "statutory responsibility to ensure security of energy supplies".
And it said the market-driven approach to deliver energy supplies was working.
Since privatisation, it said, there had never been an occasion when supply had not been sufficient to meet demand.
'If... The Lights Go Out' was broadcast on BBC Two on Wednesday, 10 March 2004.