Sir Menzies has rejigged his frontbench team

David Laws takes on the children, schools and families brief and Danny Alexander goes to work and pensions.

Lembit Opik is moved from Northern Ireland and Wales to become Lib Dem spokesman on business, enterprise and regulatory reform.

It follows reshuffles by Prime Minister Gordon Brown and Conservative leader David Cameron.

In other moves, David Heath becomes Lib Dem spokesman for justice and the Lord Chancellor's office and Susan Kramer replaces Alistair Carmichael at transport.

This is a winning team which will take the fight to the other parties as we head toward the next election Sir Menzies Campbell In full: Lib Dem front bench

Party President Simon Hughes, who last year failed in his bid to be party leader, replaces Mr Heath in shadowing Commons leader Harriet Harman.

With the education department being split in two, David Laws becomes schools spokesman, taking on Labour's Ed Balls, with Sarah Teather shunted sideways to take on new Innovation, Universities and Skills Secretary John Denham.

Mr Laws, 41, a former work and pensions spokesman, is a former City banker seen as being on the right of the party.

Danny Alexander, 34, was junior work and pension spokesman.

'Cosy consensus'

Norman Baker, who has led the campaign to protect freedom of information laws, returns to the frontbench, shadowing Cabinet Office Minister Ed Miliband.

The reshuffle is an attempt by Sir Menzies to regain the political initiative after recent opinion poll reverses and attempts by Gordon Brown to poach some of his party's biggest names.

Sir Menzies said: "We are fortunate in having some of the brightest and most able people in the House of Commons.

"I am confident they will continue to hold the government to account and develop Liberal Democrat policy.

"We must continue to attack Labour and the Conservatives for their cosy consensus on key issues from the environment and civil liberties to nuclear energy and the war in Iraq.

"This is a winning team which will take the fight to the other parties as we head toward the next election."

Brown jobs

The Lib Dem leader has seen his party's standing slip in recent opinion polls and he is under pressure to pull off strong by-election performances in Ealing Southall and Sedgefield on 19 July.

A number of leading Lib Dems have, meanwhile, accepted jobs in Gordon Brown's first government, with Lord Lester advising on constitutional reform and Baroness Neuberger advising on volunteering.

The party's former leader Lord Ashdown turned down the chance to be Northern Ireland Secretary, after consulting Sir Menzies.

The Lib Dem leader had earlier held talks with Mr Brown over members of his front bench joining the Cabinet before ruling it out.