One of Prime Minister David Cameron's closest advisers is to take a year out of politics, depriving the prime minister of a sometimes controversial strategist who helped mastermind his rise to power.

Steve Hilton, Cameron's flamboyant director of strategy famous for bicycling to work and going around Downing Street without shoes, will take a year-long unpaid academic sabbatical at Stanford University in California, starting this summer, Cameron's office said on Friday.

Cameron's blue-sky thinker, Hilton has drawn controversy for putting forward ideas - including abolishing maternity leave and suspending consumer rights laws in an effort to boost the economy - that have put him in conflict with the centre-left Liberal Democrats, minority partners in Cameron's coalition government.

The shaven-headed public relations expert was a key architect of Cameron's rise to win the leadership of the Conservative Party in 2005 and drew up some of the policies that helped the Conservatives emerge from 13 years of opposition at the 2010 election.

They include Cameron's big society policy, which encourages ordinary citizens to play a greater role in running services traditionally managed by the state.

The centre-right Conservatives failed to win an outright majority and were forced into a coalition with the Lib Dems. Some analysts said the big society idea failed to fire the imagination of voters.

A spokeswoman for Cameron said Hilton, 42, would return to the same job after spending the year in California. That would be in time to advise Cameron in the run-up to the next national election, due in 2015.

The spokeswoman gave no reason for Hilton's decision except to say he wanted to spend more time with his wife, Google executive Rachel Whetstone, and their young family.

Hilton is far from being Cameron's most controversial hire.

The prime minister was criticised for his decision to employ former News of the World tabloid editor Andy Coulson as his media chief in 2007 - accepting his assurances that he knew nothing of phone-hacking that occurred under his editorship.

The now-defunct News of the World was part of Rupert Murdoch's News Corp media empire.

Coulson resigned as an aide to Cameron in January last year and police arrested him in July on suspicion of corruption and trying to intercept communications. He was freed on police bail.

(Reporting by Adrian Croft; Editing by Ben Harding)