It started with a traffic penalty. It ended in political exile.

Former British Cabinet minister Chris Huhne - once one of the country's leading politicians- has pleaded guilty to the charge of obstruction of justice over a career-wrecking attempt to pin a speeding penalty on his wife.

Prosecutors say Huhne in 2003 persuaded economist Vicky Pryce to say she had been driving the car, so he could avoid a driving ban. Huhne repeatedly denied wrongdoing, but he was forced to step down as a minister after being charged.

His career in shambles, Huhne changed his plea from innocent to guilty at London's Southwark Crown Court on Monday. He later emerged from court to tell reporters he was resigning from his parliamentary seat as well.

Before the scandal broke, Huhne was seen as one of the nation's top politicians, only narrowly losing to Nick Clegg for the leadership of Britain's third place Liberal Democrats Party in 2007.

The Liberal Democrats went on to form a coalition with Prime Minister David Cameron's Conservative Party, handing Clegg the position of deputy prime minister. At that point, many still thought of the 58-year-old Huhne as Clegg's likely successor.

Huhne now faces the prospect of a prison term. Obstruction of justice carries a maximum sentence of life in prison, although the penalty generally averages around a year.

Pryce's willingness to take the heat for her husband did not save their marriage. The pair split in 2010 after it was revealed he had an affair with his public relations adviser. She faces a separate trial, due to begin Tuesday.

In a statement, Clegg said he was "shocked and saddened" by Huhne's guilty plea but said he had "taken the right decision" by resigning. Cameron's spokesman declined to comment on Huhne's guilty plea or resignation.