Simon Hughes, the Liberal Democrats' president, is expected to join the race today to succeed Charles Kennedy as party leader.

But a survey of all 62 Liberal Democrat MPs by The Independent yesterday shows that Sir Menzies Campbell, the bookmakers' favourite, enjoys the overwhelming backing of the party's representatives at Westminster.

Twenty-six other MPs said they would support Sir Menzies. Mr Hughes won the public backing of six MPs, although that is likely to rise today. Mark Oaten, the party's home affairs spokesman, has only one MP supporter, Lembit Opik, but is thought to enjoy the private support of the ousted leader Mr Kennedy. Friends of Mr Oaten insist he can muster the seven signatures needed to win a place on the ballot paper.

Chris Huhne, a Treasury spokesman, will decide today whether to throw his hat into the ring as a fourth candidate, amid claims by allies that he had the backing of at least seven MPs. One supporter said: "Chris is seriously considering standing and a real buzz has grown up around him. Lots of us are encouraging him to go for it. He is talking to friends and weighing up his decision. There is a real possibility he will stand, but it is not certain."

However, no MPs came out for Mr Huhne in the survey and he was under intense pressure from Sir Menzies's supporters not to stand. They said the former MEP, who has only been an MP since last May, had no chance of winning and should join fellow modernisers by rallying behind Sir Menzies. Twenty three MPs remained undeclared in the survey.

The final decision will be made by the party's 75,000 members in a ballot with the result declared on 2 March. Mr Hughes has strong grassroots support and Campbell allies admitted there could be a close contest between the two.

Mr Hughes hoped to talk to every one of his parliamentary colleagues before announcing his decision today on whether to stand. His backers hope to gather at least 10 nominations from MPs, and said he was likely to mount a leadership bid. He is on the party's left and would campaign on a social justice ticket. Opponents would portray him as a "tax-and-spend candidate" who would alienate voters in seats where the party's main battle is against the Tories.

Sir Menzies's campaign suffered a setback when he appeared at Prime Minister's Questions in his role as acting party leader. His attack on Tony Blair's public service reforms backfired when he asked the Prime Minister to explain why one in five schools do not have a permanent head teacher. MPs roared with laughter and mocked him because the Liberal Democrats do not have a permanent head.

Mr Blair replied: "As he knows, it can be difficult to find the head of an organisation when the post is vacant - particularly if it's a failing organisation." Sir Menzies took his gaffe in good part, saying: "I just knew it was going to be one of those days." One Liberal Democrat MP described it as "a gaffe that will damage Ming". A Tory MP likened it to the speech which scuppered the front-runner David Davis's campaign to win the Tory leadership.

Sir Menzies, widely respected on foreign affairs, sought to be equally effective on domestic issues by accusing the Government of "making a mess" of public service changes. The Prime Minister had abandoned socialism, he said, but Blairism was now "a byword for centralisation and failure to deliver".

Mr Blair replied by rattling off a list of the Government's achievements. He welcomed Sir Menzies as interim leader, adding that he would give him " an even bigger welcome" if it became permanent, before joking that this might be the kiss of death for his campaign.

Mr Hughes asked Mr Blair why patients had to pay thousands of pounds for private operations to beat NHS queues. To growing laughter, a smiling Mr Blair looked around for Mr Oaten, asking: "Where's the other one?" The Winchester MP, who launched his leadership bid on Tuesday, was in a television studio commenting on the Commons session for the BBC.

Who they support

SIR MENZIES CAMPBELL

Danny Alexander

Norman Baker

Tom Brake

Jeremy Browne

Malcolm Bruce

Paul Burstow

Vince Cable

Alistair Carmichael

Nick Clegg

Edward Davey

Don Foster

Andrew George

Julia Goldsworthy

Nick Harvey

Paul Keetch

Norman Lamb

David Laws

Michael Moore

Adrian Sanders

Sir Robert Smith

Matthew Taylor

Sarah Teather

Stephen Williams

Jo Swinson

John Pugh (likely)

Alan Reid (likely)

SIMON HUGHES

Tim Farron

Paul Holmes

Mark Hunter

Steve Webb

Roger Williams (likely)

Richard Younger-Ross (likely)

MARK OATEN

Lembit Opik

Charles Kennedy (likely)

UNDECLARED

John Barrett

Alan Beith

Colin Breed

Annette Brooke

Lorely Burt

Lynne Featherstone

Sandra Gidley

Mike Hancock

Evan Harris

David Heath

Martin Horwood

David Howarth

Susan Kramer

John Leech

Greg Mulholland

Dan Rogerson

Paul Rowen

Bob Russell

Andrew Stunell

John Thurso

Mark Williams

Phil Willis

Jenny Willott

OTHERS

Chris Huhne (possible candidate)

John Hemming (possible candidate)