Iranian property entrepreneur Robert Tchenguiz has quietly amassed an 8.5 per cent stake in Birmingham-based pubs group Mitchells & Butlers, it emerged yesterday.

His stake building activities are likely to fuel speculation that Mr Tchenguiz may one day return with a new bid for M&B, which recently rebuffed his initial £2.7 billion takeover proposal.

M&B, which includes Harvester in its brands, said the move, valued at 550 pence per share, from the R20 consortium led by the property magnate, under-valued the business and its prospects.

Under Takeover Panel rules Mr Tchenguiz is prohibited from a making another bid for six months.

However, he is now the third largest shareholder in M&B, which has its headquarters in Fleet Street, after his investment vehicle, Violet Capital Group, bought a 5.7 per cent equity stake in the pubs group via Luxembourg-based Kaupthing Bank.

It is not yet clear whether Mr Tchenguiz intends to increase his holding in M&B still further.

Mr Tchenguiz has rapidly built a pub empire that runs about 418 managed pubs under brands such as Slug and Lettuce, Hog's Head and Yates's. He also owns around 450 tenanted pubs.

Last week M&B, which owns the Harvester and All Bar One chains, signalled that it was on the look-out for more outlets after posting a 9.6 per cent increase in first half profits.

The group said pretax profits for the 28 weeks to April 15 came in at £91 million, while sales rose 2.7 per cent to £887 million.