One of a batch of ambitious MPs elected in 2005, Chris Huhne's profile soared when he challenged for the party leadership, coming second to Sir Menzies Campbell.
A former economics journalist and businessman, he was the Lib Dems' deputy economics spokesman before his move to the environment brief.
Mr Huhne was an MEP from 1999 to 2005, before becoming MP for Eastleigh.
Educated at Westminster School, The Sorbonne and Magdalen College, Oxford, he has written four books.
During his leadership campaign, Mr Huhne made much of his policy of introducing more "green" taxes.