Small brewers are looking for alternative sources of income to replace the brewing contracts they signed with Whitbread.
Though all contracts signed by Whitbread, which sold its breweries to Interbrew in May, will be honoured, many of them are unlikely to be renewed once they expire.
Essex brewer Ridleys agreed to take Heineken into its pub estate in return for brewing quantities of other Whitbread products such as Mackeson stout.
Dutch brewer Heineken is thought likely to review its lager brand once its contract expires in about 18 months. It is currently being brewed in the UK by Interbrew.
Managing director Greg Jephcott said: "We are looking to replace this contract. It looks as if Heineken will go its own way so we have some time to find another brewing contract." He did not say whether Heineken would be replaced on the bar at Ridleys pubs, though this seems likely as the brewer is currently in talks with Scottish Courage.
But Interbrew sales and marketing director Stewart Gilliland moved to calm speculation about the future of former Whitbread brands.
He said: "It's business as usual. The Heineken contract will remain for the foreseeable future and the brand is performing extremely well." Interbrew plans radio and poster ads for August. Gilliland added: "The long-term future is yet to be decided."
The future of Murphy's is linked to that of Heineken as the stout brand is also owned by the Dutch brewer. "Heineken could choose to leave the UK brewing of Murphy's with Interbrew," said Gilliland. The contracts to brew Murphy's and Heineken are of differing lengths.
A Heineken spokesman said no decision had yet been made.
Another UK brewer whose fortunes are linked to Interbrew is Wadworth, the Wiltshire-based brewer of 6X.
Gilliland said the brand would be treated as "our lead premium cask ale".
As to the rest of the Interbrew cask ale portfolio, including Draught Bass, cask Boddingtons, Flowers and Hancock's HB, Gilliland was less positive.
"Cask ale is declining with the trend towards nitro-keg and lager. It would be very difficult to predict that all the brands would remain with us."
He added that Interbrew would not seek to impose exclusive contracts on pub-owning companies, though freetrade licensees may be tempted to sign them through discount deals.