Scottish & Newcastle has put its entire managed pub estate up for sale for an estimated £2bn.
The company will quit pubs to focus on its global brewing operations.
It has today launched a £250m bid for troubled UK cidermaker Bulmers and is said to be interested in Danish brewer Carlsberg.
The company has always insisted it was committed to running pubs and denied sale speculation.
Until recently S&N had been in talks to sell half of its pub estate in a property deal.
Britain's biggest brewer had been expected to announce the sale of 700 pubs to Japanese bank Nomura, where S&N would sell the freeholds but retain operational control.
It is understood that Tony Froggatt, the former Seagram executive who will shortly take the reins at S&N as chief executive, was briefed over the decision to exit the UK pub sector.
If S&N is successful in acquiring Bulmers it will end 150 years of family control. Belgian brewer Interbrew is also thought to be interested and could launch a counter bid.