All the parties are staying tight-lipped at the moment but it's understood that Verizon wants to get full control of the US operation by effectively buying out Vodafone's 45 per cent shareholding in Verizon Wireless, their joint venture. AT&T would take the rest of Vodafone, securing a long-sought-after position in the European market.

By working together the two companies have enough financial bulk to pull together a deal without worrying their banks. And because they would then split the proceeds they could avoid upsetting the US regulatory authorities.

News of a possible deal comes after a long period of speculation over the future of the Vodafone/Verizon joint venture.

According to the Financial Times, the offer on the table is for 260 pence per share, around a 40 per cent uplift on the current price. That would value Vodafone, as the second-largest mobile operator in the world (after China Mobile), at US$245 billion. If successful the merger would be by far the largest corporate move in history.