In November, MPs voted to include a market rent-only option (MRO) for tied tenants in the legislation following a clause put forward by Mulholland.
However, Lord Hodgson of Astley Abbots, a former director of Marston's, has now tabled amendments to the Bill as it progresses through the House of Lords.
His amendments seek to "undermine, sidestep and water down the all important MRO", according to Mulholland. They include an option for opting out of MRO, inserting further lengthy consultation periods before the legislation can have effect, and a revised clause which means that only future entrants to the pub industry will have the protection of MRO.
Lord Hodgson was a director of Marston’s for 12 years up until January 2014. His speech in the second reading debate in the House of Lords drew ridicule when he claimed that pub closures were caused not by the unfair pubco tied business model, but by an increase in the Muslim population.
'Rotten'
Mulholland said peers supporting the Fair Deal for Your Local campaign would oppose all of Lord Hodgson’s amendments.
"Many people will feel there is something rotten about an unelected peer, who only stepped down as a director of Marston’s in 2014, tabling amendments in support of his pubco friends," he said.
"Thankfully there are many peers who fully support the Fair Deal for Your Local campaign, CAMRA and the small business organisations and I am confident that they will oppose all these pro-pubco anti-reform amendments.
"MPs sent a very clear message that they support the BIS Select Committee solution, the market rent-only option and any attempt to undermine this must be stopped in its tracks."
The Grand Committee stage is followed by Report Stage in the Lords, before the Bill comes back to the Commons for the final chance for the Government to seek to reverse any changes the Lords have made.