Low incomes, rising rents and high running costs are driving publicans in Reading, Berkshire out of the trade, it has been claimed.
A local councllior has slammed pubcos, accusing them of "twisting the knife" with tied licensees, and calling for a change in the law.
The attack on the pubcos was made by Liberal Democrat Gareth Epps, a local councillor and parliamentary campaigner, following a survey of pubs in the Reading East constituency.
Three-quarters of publicans responding to the survey have an annual income below £15,000 a year, and only half think they will be still running a pub in five years' time.
Rent and running costs were the two biggest concerns for publicans, ahead of the impact of higher beer duty.
In all, 80 per cent of responses came from tenants and lessees of pubcos, including Enterprise Inns and Admiral Taverns.
These licensees objected to the high cost of buying tied products, as well as having monitoring equipment installed in their cellars.
Cllr Epps has submitted a report on his findings to the OFT, which is currently investigating the beer tie, as well as discussing them with All-Party Save the Pub Parliamentary Group chair Greg Mulholland MP.
Cllr Epps said: "These findings show that there are many threats to Reading's community pubs - but one of the biggest are the companies that own the pubs themselves.
"While increased taxation by the Labour government, cut price supermarket booze and the smoking ban haven't helped, it's the pubcos that twist the knife."