Chris Huhne has never shied away from political controversy - but it is his desperation to avoid a speeding ban that has finally put the brakes on his high-flying career.
Often outspoken and fiercely ambitious, Mr Huhne thrust himself into the front ranks of his party by coming close to snatching the leadership just eight months after first becoming an MP in 2005.
In 2007, he was once again a narrow runner-up, this time to Nick Clegg in a sometimes rancorous contest in which the now Deputy PM was branded ''Calamity Clegg'' by team Huhne.
His high profile made him an obvious candidate to join the negotiating team that struck a coalition deal with the Tories, though he admitted it involved ''unpleasant'' compromises.
Among them was nuclear power - a issue on which as Energy Secretary he has trodden a tightrope between his party's ultra-green grassroots and Chancellor George Osborne's austerity drive.
He has forged a positive reputation for much of his work to push the green agenda - including achieving modest progress in ''anarchic'' global climate change talks in Cancun, Mexico.
But within weeks of taking office, Mr Huhne suffered the first in a string of negative newspaper stories sparked by issues outside of his departmental brief.
Newspapers uncovered his ''serious'' relationship with former aide Carina Trimingham, forcing him to announce that he was separating from his wife, Greek-born government economist Vicky Pryce.
She has revealed that he broke the news to her during half-time of a televised World Cup match - and then immediately went to his study to write the statement and send it out to the press.
The end of the 26-year marriage between the couple, who have three children together, was confirmed in a 2011 divorce announcement - but it would prove far from the end of the story.
In the meantime, it was another marriage - with the Conservatives - that was also proving somewhat rocky as Mr Huhne riled backbench Tories with a string of digs.
He publicly suggested spending cuts may have to be reined in, blamed Tories in his constituency for closing children's centres and appeared to clash with the Chancellor over green energy.
The most virulent attacks on coalition colleagues were over what he claimed were smears and lies in anti-AV leaflets, as the governing partners took opposing sides in the vote reform referendum.
Quite apart from accusing Tory chairman Baroness Warsi of issuing Nazi-style propaganda, he directly confronted Prime Minister David Cameron in an outburst across the Cabinet table itself.
Later he dismissed as a ''fairly marginal mistake'' the accidental publication of a private message apparently showing he was keen for a media story about the Tories not to be linked back to him.
A sometimes abrasive style has won him few friends among Tories - and even Mr Clegg felt able publicly to make a jibe at the expense of his colleague's biggest challenge to date.
''Whatever people say or think about Chris Huhne, I really don't know any politician who is better at getting his points across,'' the party leader joked to reporters at a Westminster lunch.
He has spoken subsequently of his ''enormous regret'' at the bitter break-up with Pryce and revealed that he had apologised but that his plea for forgiveness was rebuffed.
Born in July 1954, Huhne was educated - like Mr Clegg - at Westminster School before going on to the Sorbonne in Paris and Magdalen College, Oxford.
Entering journalism he became economic commentator for The Guardian, The Independent and The Independent on Sunday, as well as working for the Liverpool Daily Post and Echo and The Economist and was named financial journalist of the year in 1990.
In 1994, he founded one of the largest teams of economists in the City and he is the author of four books - the most recent an argument for British membership of the euro.
Elected as a Member of the European Parliament for south-east England from 1999, he became the Liberal Democrat group's deputy leader and served on the Economic and Monetary Affairs Committee.
His victory at Eastleigh in the 2005 election followed defeats in Reading East and Oxford West and Abingdon during the 1980s.
In the 2010 general election he held the Hampshire constituency with slim majority of just 3,864 - a significant advance on the wafer-thin 568 vote margin by which he won the first time.
In the most recent edition of a parliamentary book, he lists his interests as family, football, cinema and history.
During the last leadership contest, one newspaper uncovered a bizarre article published under Mr Huhne's byline in a 1970s student magazine, which advocated the tolerance of class A drugs such as opium and LSD. Mr Huhne claimed not to remember whether he had written it.