Johnson, now chairman of the Belgo restaurant group, has gone in with Morgan Grenfell Private Equity to make a sudden and unexpected late entry in the £1.7bn auction. Johnson's offer is said to have been put together in less than two weeks
Meanwhile Osmond, chief executive of the UK's second-biggest pub operator, Punch Group, has allegedly been approached by several investment banks who would like to finance a bid for the Whitbread estate.
However, Osmond said although he was looking at a bid for the whole Whitbread estate, he was not working with any partners at the moment, though he was "open to potential interest" in Whitbread's high street pub sites where Punch has chosen not to focus.
The Punch offer would be mostly in cash but shareholders could also be offered an option over equity in the enlarged Punch group. This would be valuable if, as is likely, Punch is floated in the future.
Osmond said there were synergies of £30m that could be found from joining its managed pubs and Whitbread's managed estate to form a managed pub division of 2,000 units that could compete with the size of Bass's and Scottish & Newcastle's managed estates.
Punch first made an indicative offer for Whitbread in December after the group put its pub estate on the market to focus on restaurants and leisure.
Osmond said the Whitbread pubs had seen more investment than the Allied Punch bought two years ago, so there would be less "upside" potential. However, he said, the Whitbread estate was strong in the affluent South East of England and its smaller pubs would fit well into Punch's estate.
The other bidders for Whitbread's pubs are
Nomura's Principal Finance Group and already the biggest pub landlord in the UK after adding almost 1,000 Bass pubs to its empire last month, and Candover, another venture capitalist, which is bidding in conjunction with the pubco Pubmaster.
• Punch grew quickly after buying Bass's leased pub estate in 1997 and then Allied Domecqs 3,500 pubs in September 1999 for £2.75bn,after a fight with Whitbread, before selling on the largest 550 Allied pubs to Bass for £920m.
A successful bid this time would end up with Punch owning the majority of both Allied's and Whitbread's pub estate. Already Punch and Nomura between them own nearly one in five of Britain's 60,000 pubs.
• Johnson is believed to have gone to Morgan Grenfell after his previous backer, Schroder Ventures, decided to withdraw earlier. The debt financing is coming from Lehman Brothers.