Safeway is a one-off opportunity - it is never going to be available again Philip Green

The move - which could happen within the next 10 days - will put pressure on US giant Wal-Mart to show its hand, as the six way battle to acquire the supermarket group intensifies.

The Sunday Telegraph said Mr Green and business partner Allan Leighton were meeting with Office of Fair Trading officials this week.

It added the retail tycoon was preparing a bid of at least 300p per share and has already lined up three candidates for the chief executive role.

Outflanking rivals

Mr Green told the newspaper: "Safeway is a one-off opportunity. It is never going to be available again."

This is now set to be one of those landmark takeover battles - a rare contest that will change forever one of our biggest industries Declan Curry BBC business presenter

Analysis: The Safeway bidding frenzy

Meanwhile, Sainsbury is reportedly planning to team up with Morrisons in an attempt to outflank rival potential bidders Asda and Tesco.

Sainsbury could beef up Morrison's all-share offer for Safeway with a cash injection, reports the Observer.

If Morrison won, Sainsbury would want certain flagship stores to the value of the cash advanced, it adds.

Unexpected boost

A Sainsbury spokeswoman dismissed talk of a tie-up as "rumour and speculation".

But Sainsbury chairman Sir Peter Davis is thought to be considering all options, the Observer writes.

US buyout giant Kohlberg Kravis Roberts is the sixth potential bidder to have shown an interest since Morrisons agreed a �2.9bn deal on 9 January.

Safeway's recommendation of the Morrisons' offer was dropped last week.

The supermarket group then upped the stakes further on Friday by announcing its property assets were worth more than expected.

Who blinks first?

Independent valuation in October estimated the value of 201 of its top stores at �4.5bn - an increase of nearly �2bn, the company said.

The bidders

Morrisons Sainsbury Philip Green Kohlberg Kravis Roberts Asda/Wal-Mart Tesco

Analysts believed Safeway was attempting to push its sale price towards the 400p per share mark - a market value of �4.2bn.

It is thought both KKR and Wal-Mart are poised to publicise how much they are willing to spend.

But they are waiting for each other to show their hands first.

Higher offer

If Mr Green goes ahead with his bid, it will put pressure on his rivals given his bid is unlikely to be referred to the competition authorities.

The Monaco-based billionaire owns one of the UK's largest clothing businesses after buying BHS and Top Shop group Arcadia.

But he currently has no interests in the food retail sector.

Morrisons is the only one of the six to have formally proposed a deal and could still come back with a higher offer.

But its falling share price has pushed the value of its all-paper bid for Safeway down by �500m in the past fortnight to �2.4bn.