Vince Cable is to stand down as Liberal Democrat deputy leader to concentrate on his job as business secretary.
Mr Cable, who has held the party role since 2006 and served as acting party leader in 2007, is one of five Lib Dem MPs in the coalition cabinet.
He said he wanted to focus on the challenges of his government role and stressed the Lib Dems had a "real opportunity" to change Britain.
The party will elect a new deputy to leader Nick Clegg on 9 June.
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