LONDON — A former British government minister announced his resignation from Parliament on Monday, after reversing his longstanding denials to accept responsibility for persuading his former wife to take the blame for a speeding offense he had committed a decade ago.

The resignation of the minister, Chris Huhne, 58, a onetime contender to lead the Liberal Democrats, the junior partner in the coalition government, was a tacit acknowledgment of the end of what had once been a high-flying career. “Having taken responsibility for something that happened 10 years ago, the only proper course of action for me is to resign,” he said.

Until now, he had steadfastly denied that, in 2003, he persuaded his then-wife, Vicky Pryce, to say she had been at the wheel when their car was caught in a highway speed trap between Stansted Airport and London. Had he admitted the offense at the time, he could have been banned from driving. The case emerged in 2011, after the marriage broke up over an affair he had and Ms. Pryce pleaded not guilty to perverting the course of justice in the episode, saying she had been coerced.