Robert Tchenguiz, the Iranian property tycoon, bought another 70 million shares in J Sainsbury yesterday, raising his stake in the supermarket to 4.04 per cent, from 3.95 per cent previously.

Sources said that, having bought his stake at an average of 530p, Mr Tchenguiz was taking a bet on a bid of at least 550p from the CVC-led private equity consortium that is in talks with Sainsbury’s advisers.

One source said last night: “It is an investment. If they bid at less than 550p, then he thinks it is undervalued.”

Other sources said that Mr Tchenguiz was hoping to use his stake to help to negotiate a deal with Sainsbury’s in which he would help the supermarket chain to set up a separate property company to handle its freehold assets.

The bidding group led by CVC is awaiting a response from Sainsbury’s pension fund trustees on a proposal to make an upfront lump sum payment into the fund and then clear the remaining deficit, last valued at £477 million under IAS19, over several years.

It is thought unlikely that the trustees will come back with an answer until the end of this week.

A deal with the trustees is a vital stepping stone towards setting a firm price for any deal by the CVC consortium.

Yesterday, Sainsbury’s shares held up on hopes of a rival bid emerging from a consortium led by Bain Capital, the American private equity firm. However, the consortium did not put out a statement confirming interest yesterday, leading some investors to speculate that Bain did not have a serious intent to bid.

The news of Mr Tchenguiz’s stakebuilding came amid fresh speculation that he is putting pressure on Mitchells & Butlers, the pub operator, to consider spinning off its property assets into a real estate investment trust (Reit).

The All Bar One and Harvester operator is expected to update investors on its plans when it announces its interim results on May 22.

However, Geof Collyer, leisure analyst at Deutsche Bank, said in a research note yesterday: “We believe that better longer value for shareholders can be generated by not converting into a Reit and an operating company.”

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