Centrica, the owner of British Gas, was last night considering a £1.1 billion takeover of Venture Production, the North Sea gas producer, after snapping up nearly a quarter of the company's shares in a move to bolster its supplies of the fuel.

Centrica said that it had paid £239 million for 33 million shares in Aberdeen-based Venture yesterday at 725p each, representing a 22.3 per cent stake in the company. It is thought to have bought the shares from Aberdeen Asset Management and Schroders.

In a statement, it said that it was considering a cash offer for the remaining shares. If approved, such a deal would value Venture, the tenth-largest holder of gas reserves in the UK sector of the North Sea, at just under £1.1 billion.

Mike Wagstaff, Venture's chief executive, dismissed Centrica's approach as “highly opportunistic” amid the market turmoil and said that it “substantially undervalued” the company, which is in the midst of an exploratory drilling programme.

Centrica, which supplies gas to 9.7 million British households, or 45 per cent of the total market, is keen to use the recession as an opportunity to strengthen its access to resources that a year ago were trading at dizzying valuations.

The company's gas production provides only 29 per cent of UK requirements, forcing it to buy the remainder on volatile wholesale markets. An acquisition of Venture would increase that to about 40 per cent and nearly double Centrica's total reserves base from 238 million to 452 million barrels of oil equivalent.

Mr Wagstaff said that he was urging shareholders not to sell and that Venture, whose fields lie mainly in the southern part of the North Sea, was drilling another 15 wells this year, which could increase its reserve base.

He said that the price at which Centrica had bought shares valued Venture's reserves at just $8.80 per barrel of oil, compared with the market price of about $45.

Centrica's interest in Venture does not rule out the possibility of it completing a £3.1 billion acquisition of a 25 per cent stake in British Energy, the UK nuclear generator now owned by EDF of France.

Centrica has more than £5 billion of funding at its disposal so could comfortably complete both transactions. It raised nearly £2.2 billion in a rights issue before Christmas and a further £2.4 billion in a series of bond issues. It also has roughly £1 billion in additional bank facilities.

Talks about the British Energy deal have dragged on for longer than expected, amid growing concern among investors that Centrica risks overpaying for the stake. It announced its intention to purchase the stake in September just before share prices and wholesale electricity prices collapsed.

Centrica is believed to be discussing potential sweeteners with EDF to make the deal more palatable to sceptical shareholders. These are believed to include an asset swap, possibly of SPE, a Belgian utility in which Centrica holds an equity stake.

However, Sam Laidlaw, the chief executive of Centrica, said last month that the company would consider dropping the deal if it did not create value for shareholders.

Venture's shares soared after the announcement of an approach from Centrica, rising by 154p to 734p.

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