Gordon Brown, Alistair Darling and other cabinet ministers have been calling wavering MPs as Labour whips prepare for a close vote next week over moves to streamline the planning system.
The prime minister and chancellor are concerned about a fresh backbench rebellion just days after the government pushed through its anti-terror bill with a majority of only nine, aided by the Democratic Unionists.
The controversy is over proposals that would strip local councils of their right to adjudicate on all big projects, from Heathrow’s new runway to new nuclear power stations, and leave the decision in the hands of an independent commission.
Some Labour MPs fear this quango is not democratically accountable because its members will not be elected.
Instead, they argue, there should be a ministerial veto over large infrastructure projects and are likely to join the Conservatives and Liberal Democrats in backing an amendment – put forward by Labour MP Clive Betts – to this end.
Hazel Blears, communities secretary, will hold talks with MPs early next week to appeal for their loyalty.
The prime minister has called MPs directly to lobby them over the issue, although Downing Street said on Friday that it had no knowledge of his direct involvement.
“The fact that they’re sending secretaries of state running around means they understand that we are upset,” said David Drew, MP for Stroud.
Ministers from the Department for Communities and Local Government are holding out the possibility of some kind of compromise such as introducing new checks and balances over the committee’s powers.
The vote, on Wednesday, is still likely to be close, given that a related part of the same planning bill – an amendment calling for projects to be considered on their environmental impact – was rejected by only 15 votes earlier this month.
John Grogan, MP for Selby, said: “I think there will be a significant rebellion because there is a strong feeling on the Labour benches that ultimately it should be ministers deciding and not a quango.”
The government sees the bill as one of its key pro-business measures. “The stakes are higher than normal for that reason,” said one aide, who said a “hard-core of potential rebels” remained despite the whips’ efforts.
Labour has put a three-line whip on MPs to attend the debate while hoping that many opposition members will be engaged elsewhere ahead of Thursday’s Henley by-election.
One Tory whip indicated that the vote would be close: “The government is worried about this, and if the government is worried, we are very interested.”
More than 60 Labour MPs have signed an early day motion calling for more ministerial oversight of the process. Mr Betts agreed the planning system needed reform because “it shouldn’t take 10 years to decide on projects” such as nuclear reactors. But he said: “What I’m trying to do is ensure an improved process so we have greater accountability.”