Allan Leighton may be the future boss of Sainsbury's

Most say Mr Leighton has approached members of the Sainsbury family, who still own about a 35% stake in the firm, to try to secure their backing.

The bid could be worth as much as �5bn ($9.2bn), the Mail on Sunday said.

Yet the Sunday Times said Mr Leighton will try to install a new management team rather than make an outright bid.

Trailing rivals

Sainsbury's, the UK's third largest supermarket group, is vulnerable to a takeover as it continues to struggle to turn around the business and recover ground lost to market leaders Tesco and Asda.

Supermarket share Tesco - 28% Asda - 16.9% Sainsbury's - 15.3%

Since the start of this year it has been forced to issue three separate profit warnings, and its shares have underperformed its rivals by 23%.

Two weeks ago it announced the start of a �550m restructuring and recovery strategy that will mean it makes a loss for the year.

Speculation that Mr Leighton could be planning a bid for Sainsbury's has increased since he resigned last week from three separate directorships with internet travel website Lastminute.com, appliance maker Dyson, and leisure business Cannons.

A number of media reports have suggested that he wanted to free up time to concentrate on looking at Sainsbury's. Mr Leighton remains, however, chairman of the Royal Mail.

Too cheap?

The Mail on Sunday suggested that Mr Leighton would prefer to make his bid early in the New Year, while the Sunday Times said members of the Sainsbury's family and other shareholders would be unlikely to sell at Sainsbury's current share price (Friday's close was 258p), because they believe it undervalues the company.

"We have not sold because of the depressed share price," Andrew Cahn, a trustee of the Gatsby Charitable Trust, Sainsbury's fourth largest shareholder, told the Sunday Times.

Sainsbury's refused to elaborate on the reports.

"We don't comment on market speculation," a spokeswoman said.