Vodafone, the UK-based international mobile phone operator, is proposing to merge with AirTouch in a deal that values the US-based cellular phone company at about $55 billion.

The offer is an attempt to land a knock-out blow against Bell Atlantic, the US regional telecoms operating company, that is preparing a takeover offer for AirTouch worth about $45 billion, or $74 a share. Bell Atlantic and AirTouch have confirmed they are in talks.

If Vodafone's pre-emptive strike is successful, it would be one of the 10 biggest deals of all time, creating the world's largest mobile phone group with a market capitalisation of about $110 billion.

The bid, mainly stock but with a small element of cash, was submitted by Goldman Sachs, Vodafone's financial adviser, over the weekend following the disclosure last week that Bell Atlantic and AirTouch were in negotiations.