Nick Clegg is engaged in a series of last-minute talks with senior Liberal Democrats in an attempt to head off a rebellion at the party's spring conference in Sheffield next week.
Mr Clegg has met a number of backbench MPs, council leaders and peers to shore up his support and limit the damage from Thursday's disastrous by-election result in Barnsley.
The Liberal Democrat leadership fears that anxiety over the party's poor poll ratings and the prospect of losing control of several large city councils in May's local elections could spill over into open revolt. It is expecting rank-and-file rebellions over the Coalition's NHS reform policy and condemnation from the floor over tuition fees.
On top of that, thousands of union members and student protesters are set to picket the conference, which will be particularly embarrassing for Mr Clegg as he is a Sheffield MP.
One of those Mr Clegg is understood to have met is Greg Mulholland, the head of the newly formed Liberal Democrat Backbench Group. He has also spoken with Warren Bradley, the Liberal Democrat leader of Liverpool council and a critic of higher tuition fees. Mr Bradley has warned that the Coalition's cuts could result in the Liberal Democrats being wiped out in the North within five years.
Among others contacted by Mr Clegg are the Newcastle council leader, John Shipley; Richard Kemp of the Local Government Association; and the Liberal Democrat leader of Sheffield City Council, Paul Scriven.
He has warned them that if the party's disagreements are aired in public, this could damage their prospects in May's council elections as well as the chance of securing a Yes vote in the referendum on voting reform. Mr Clegg will unveil a slogan for the conference: "In government and on your side".
The Deputy Prime Minister will arrive in Sheffield on Thursday and attempt to seize the initiative by getting "out and about" with visits to Sheffield Wednesday football club and a high-profile campaign knocking on doors with activists.
A senior Liberal Democrat said: "He'll be reminding people not to forget what we have done. The theme will be resilience. You can't change your philosophy just because you get a drubbing in Barnsley."
Today the Labour leader, Ed Miliband, will turn up the heat on Mr Clegg after his party finished sixth in the Barnsley by-election, behind Ukip and the British National Party. He is due to give a speech suggesting the Liberal Democrats are no longer a distinctive force. "I think it's becoming clear that while there might still be three main political parties, there are only two directions for the future of our country," he will say.
As expected, Labour cruised to victory in a seat vacated by former MP Eric Illsley, who was jailed last month for expenses fraud. His successor, Dan Jarvis, increased Labour's majority to 60.8 per cent. The Liberal Democrats' vote share tumbled from 17.28 per cent to just 4.18 per cent, and the Conservatives' from 17.26 per cent to 8.25 per cent, as Ukip claimed second place.