Greg Mulholland has raised a question in Parliament over the attitude of Enterprise Inns towards MPs on the Business and Enterprise Committee.
On Tuesday, Committee chairman Peter Luff said that he had been "bitterly disappointed" by the reaction of certain pubcos to the summer's report. He said: "I am not used to being unable to comment on my own reports for fear of litigation."
In the House yesterday, Lib Dem MP Mulholland said: "I need to bring to the attention of the House a separate, very important and worrying matter. Enterprise Inns is Britain's most notorious pubco.
"Its reputation is shown by its incredible litigiousness. It has tried to sue local media and national media, and has indeed threatened hon.Members of this House.
"I do not know if you are aware of this, but Enterprise Inns has sought by way of legal threat and intimidation to prevent the Business and Enterprise Committee from carrying out its scrutiny of the activities of the pub company."
But he was told by the Speaker, he should not have raised the issue on the floor.
The Speaker replied: "I have listened very carefully to what the hon. Gentleman has said, which is certainly a matter of the highest importance to him and to many others.
"However, I have to say to him at this stage that if he has a complaint about a breach of the privilege of the House, that is a matter about which, in the first instance, he should come to me, or it is open to him to write to me, but he should not in the first instance raise it on the Floor of the House.
"Those options are open to the hon. Gentleman. If he wishes to pursue the matter with me in one or other of the ways that I have suggested, I will be all agog to hear what he has to say."