Thousands of publicans are expected to press for damages against Japanese bank Nomura, owner of former pub estate Inntrepreneur, after a new advertising campaign invited licensees to submit claims.
The campaign follows a test case brought by licensee Bernie Crehan who claimed the beer tie in the lease he signed with Inntrepreneur in the 1990s breached competition laws.
Mr Crehan won the case in the European Court of Justice late last year and the decision was subsequently upheld by the Court of Appeal.
Now campaigners are placing adverts in the national press calling for hundreds of other tenants who signed similar leases to begin legal action.
If they are successful, the bill for Nomura could run into millions of pounds.
They claim their businesses suffered at the hands of Inntrepreneur and Courage during the early 1990s because of high rents and higher prices for beer than they would have paid on the open market.
The bulk of the Inntrepreneur estate has now been integrated into the Unique Pub Company, also owned by Nomura, under new lease agreements. But former Inntrepreneur lessees could still be eligible to backdate claims.
Alan Temple, chairman of the Courage Leaseholders' Association, has been campaigning against anti-competitive practices in the industry for many years. He has now set up Inn Claims, a phone line and advertising campaign, to encourage more tenants to come forward and make a claim.
"We want to assisting current and former leaseholders. Our intention is to help them to recover the losses they suffered as a result of these illegal leases," Mr Temple said.
Inn Claims has sent out thousands of letters inviting ex-Inntrepreneur leaseholders to make a claim for damages against their former landlord.
The mail shot will be supported by a national advertising campaign aiming to make contact with about 8,000 current and former Courage/Inntrepreneur leaseholders.
He added he was expecting about 2,000 claimants to take action - which could cost Nomura up to £1bn.
But a spokesman for Inntrepreneur said Inn Claims was being premature. "The European Court of Justice ruling last year did not award any right to any damages against Inntrepreneur and any case brought will have to be argued in court on its own merits," he said.
Inn Claims can be reached 0800 132143.