Nick Clegg was tipped to be a Liberal Democrat leader before he even arrived in Parliament and is now the bookmakers' odds-on favourite for the role.

The Sheffield Hallam MP and Lib Dem home affairs spokesman has been seen as the most likely successor to Sir Menzies Campbell since he refused to challenge him in the race to replace Charles Kennedy last year.

And while the sudden resignation of Sir Menzies means the opportunity may have come sooner than expected for the 40-year-old, he is still expected to see off the challenge of his main rival Chris Huhne.

A bright, telegenic, natural media performer, Clegg is seen as the closest Lib Dem equivalent to David Cameron.

That comparison to the Conservative leader - and his somewhat undeserved label of being on the economic liberal right of the party - could count against him.

However having made his mark in the key home affairs brief he is likely to be backed by a large number of Lib Dem MPs who see him as their best chance of defending marginal seats in the south of England against the Tories.

An MEP for one term in the East Midlands from 1999 to 2004, Clegg was elected to the Commons only at the last general election in 2005.

However his time in the European Parliament and previously in Brussels as an adviser to Conservative UK commissioner Lord Brittan, had seen him marked down as a rising star.

Upon his election he was immediately made number two to Sir Menzies when then leader Charles Kennedy appointed his Lib Dem foreign affairs team.

But despite that show of faith, Clegg was one of 25 frontbench MPs who helped trigger Kennedy's resignation by refusing to serve under him as details of his alcohol problems emerged.

Having refused some invitations to stand in the subsequent leadership election, he became a key supporter of Sir Menzies and was rewarded with the home affairs portfolio.

In it, he has sought to sharpen up the Lib Dem message on crime, calling for tougher sentences for the most serious offenders and more effective community punishments for the rest.

He has also campaigned against the government's terrorism laws and identity cards, criticising them as the "politics of fear" and the wrong way to tackle extremism.

At this year's Lib Dem conference he also pushed through plans for a controversial "earned amnesty" for illegal immigrants who have been in Britain for at least 10 years.

As criticism of Sir Menzies' performance mounted, Clegg remained a loyal supporter of his leadership.

However he raised eyebrows at the Brighton conference by admitting that he "probably would" stand to replace Sir Menzies whenever he did step down.

He also said the party must reach out to new voters with an "edgy" agenda that addresses the public's concerns. And he is cool on the idea of a coalition with either of the two main parties without a meaningful change in their approach.

Educated at Westminster School and Cambridge University, Clegg, who speaks five languages, later trained as journalist in New York and joined a lobbying firm in London before moving to Brussels.

He is married to Spanish-born Miriam Gonzalez Durantez, also a former European Commission official, with whom he has two sons.