Walsall MP David Winnick was silenced by the Speaker as he attempted to discuss MPs' expenses in the House of Commons yesterday.
Mr Winnick (Lab Walsall North) criticised the decision by House of Commons authorities to fight demands to reveal how MPs have spent their second home allowances.
The Commons Commission, which manages House affairs, is to ask the High Court to rule that MPs can keep details of their spending secret.
But Mr Winnick was interrupted as he tried to raise the issue.
The Speaker, Michael Martin, said MPs were barred from discussing it in the Commons because it was a matter for the courts.
He said: "This matter is before the court and therefore it is sub-judice for the House of Commons. I know that the media can talk about it, but for the House of Commons the rules are quite clear."
The Commons is attempting to block a request for a detailed breakdown of spending by 14 high-profile MPs, including Gordon Brown and David Cameron.
The allowance is designed to help them pay for second homes in London, on the grounds that many MPs need properties close to Parliament as well as in their constituencies in order to do their jobs.
But it has emerged that the allowance can be used for luxuries such as state-of-the-art televisions and new bathrooms, all at the taxpayer's expense.
The Commission is appealing against an earlier ruling that it must reveal how MPs spend the money, on the grounds that this would mean giving out their addresses and could put their security at risk.
But Mr Winnick had been planning to argue that Parliament must be more transparent, before he was silenced.
Speaking outside the Chamber, he said: "I understand the concern about publishing everyone's full address, but I believe the commission is wrong on the wider issues.
"If we lose this appeal, it simply means that a lot more money will have been spent on lawyers.
"If we win, I'm afraid the media and much of the public will think that the judges and the politicians are in it together."
He had no quarrel with the Speaker, he said. "If the Speaker is advised that it is sub-judice then he must follow that advice."