The Commons debate over a bid to exempt Parliament from the Freedom of Information Act has been deferred until later this month, in a move that opponents of the bill fear is designed to "rally the troops" to support it.
Opponents of the Freedom of Information (Amendment) Bill had expected it to return to the chamber for further discussion last week.
But in a surprise move, former Tory chief whip David Maclean's bill to exempt MPs and peers from FoI laws was dropped from the order paper for debate.
Commons officials confirmed that Maclean had not put the bill down for consideration, but said it was expected to return on 18 May.
One of the bill's main critics, Labour's David Winnick, warned that the delay might be an attempt to win more time to muster support for the measure.
Under a point of order as business got under way, Winnick said: "There will be some surprise, I'm sure, that the Freedom of Information Bill isn't to be debated today.
"It was due to be the second item and there is a feeling that it has been withdrawn."
He told Deputy Speaker Sylvia Heal: "Many of us believe that it is just a ploy to bring the troops in on 18 May so there will be over 100 to try and pass the bill.
"Those of us who are opposed and consider it would be a disgrace if this bill were passed will be here on 18 May."
Heal confirmed that the bill was deferred until 18 May, adding that the decision was entirely up to the MP sponsoring the bill.
Winnick's reference to 100 MPs relates to the number required to close debate and force a vote on any amendment in a bid to prevent filibustering by critics of the measure.
Winnick was among a tiny band of MPs, including Liberal Democrat MP Norman Baker, who fought a fierce rearguard action two weeks ago to block the bill's progress.
The cross-party group of opponents succeeded in blocking the bill by tabling a series of amendments and talking on them for five hours.
Opponents of the bill thought they had killed it off when time ran out but a quirk of parliamentary procedure meant that it returned to the order paper last week.
It was initially the first item on the day's agenda, but was then "leapfrogged" by two other bills.
Supporters of Maclean's measure say it is needed to protect the confidentiality of MPs' correspondence with constituents, but critics say correspondence is already exempt under the Freedom of Information Act.
The Government has insisted it is adopting a neutral attitude to the proposals, but its lack of opposition so far has suggested that it tacitly supports the bill.
Several ministers – including Tessa Jowell, Tony McNulty, Andy Burnham, Ian Pearson and John Healey – voted in favour of the legislation two weeks ago.
Hughes said MPs should be given better notice when a bill's debate date was changed.
Heal said "nothing irregular or improper" had taken place and it was incumbent on MPs to keep in regular contact with the table office to find out what was happening.