Verizon Communications and AT&T have been studying a possible joint takeover of Vodafone, according to the Financial Times’ Alphaville blog.

The potential offer would be pitched at around a 40 per cent premium to Vodafone’s current share price, valuing the UK operator at about $245 billion and making the deal, if it happened, the largest M&A transaction in history.

The blog quoted “usually reliable people” as sources for the story.

The deal would be structured so that Verizon gets hold of Vodafone’s 45 per cent stake in the Verizon Wireless joint venture while AT&T takes Vodafone’s assets outside the US.

Barclays US is working on the transaction for the two US operators.

The involvement of AT&T could supply the means to finally break the deadlock on Verizon Wireless’ ownership. According to David Barden, a mobile analyst with Merrill Lynch, AT&T’s involvement “might be the only way that eight years of stalled talks to resolve the Verizon-Vodafone partnership could be bridged with each party getting what they want…”

Vodafone and Verizon have previously discussed a number of other options, including a full merger which was on the agenda as recently as December, according to a report last month. However, a buyout or partial sale have now become more likely approaches, the report said.

Meanwhile, AT&T was reported in January to be looking at an acquisition of a counterpart in Europe. Acquiring Vodafone – with its significant presence in markets including Germany, UK, Italy and Spain – would fit with that strategy.