Electricity generator National Power was yesterday at the centre of renewed takeover speculation as the City pondered the prospect of a #10 billion bid for the company.

A fall in the company's share price, 560p at Friday's close against a year high of 694p, has led to repeated City rumours that it might be vulnerable to an offer from overseas.

Two years ago an approach for the company - Britain's biggest conventional power generator - by Southern Company of Atlanta, owner of regional electricity company Sweb, was foiled when the Conservative government exercised its controlling golden share.

According to a report in The Sunday Times, a new attempt is being made to put together a consortium to make a new bid for the privatised company.

Among the companies said to be potential consortium members are Japanese finance house Nomura, and Industrial Bank of Japan, along with US power companies Southern, Pacific Gas, and Edison International.

But a spokesman for Swindon-based National Power responded: ''It is purely speculation.''

Because the Government still owns a golden share in National Power, any takeover bid would be a political hot potato.

Two years ago, National Power's bid for regional electricity company (REC) Southern Electric was blocked when the Conservative government voiced concerns about generators buying RECs.

But some observers believe the climate has changed since 1996 and cite President of the Board of Trade Margaret Beckett's clearance of the recent US takeover of Energy Group, owner of Eastern Electricity, as evidence that a new bid might not get such a rough ride from the regulators.

Last week the National Power unveiled plans to invest #155m in two power station projects in China, taking its total overseas investment to #1300m and making it a major international player.