Many UK power stations will near the end of their working lives

PowerGen says that �50bn-�70bn will be needed to upgrade the network as coal-fuelled power stations reach the end of their working lives.

The warning came after a survey found that fear of a blackout was the top concern of European businesses.

Demand for power is outstripping supply, the study said.

Nine out of 10 companies polled by accountancy firm PricewaterhouseCoopers said they expected frequent disruptions to power supplies across Europe.

Lights out

Last August a major blackout in south London stranded 300 tube trains and only a month ago a power failure plunged 61,000 homes in Wiltshire into darkness.

We will have to get used to paying more for our electricity in the future Dr Paul Golby, PowerGen chief executive

But the worst example took place in North America when tens of millions of people in Canada and north-eastern US were left without power for two days last summer - all because of a crumbling power network.

With world energy demand expected to rise by two-thirds between 2003 and 2030, about �5,600bn of investment is needed in the energy sector - three times more than in the past 30 years.

"We can't live modern life without electricity and there is now a major need to invest in the UK," PowerGen's chief executive Dr Paul Golby told BBC Radio 4's Today programme.

"Over the next decade, we probably need to spend �50bn-�70bn to replace ageing power stations and overhead cables.