David Cameron's director of strategy Steve Hilton is to leave Downing Street for a year in order to teach in California, it has been announced.
According to No.10 Hilton will take take an unpaid academic sabbatical at Stanford University, starting this summer.
"With his wife and young family, Steve will be moving to California. He will join Stanford as a visiting scholar at the university’s Freeman Spogli Institute for International Studies, and will also be a visiting fellow at Stanford’s Hoover Institution," a spokesperson said.
"He will spend his year on campus teaching, researching and writing, and will focus on innovation in government, public services and communities around the world."
Hilton has been a key member of the prime minister's inner circle and helped lead efforts to detoxify' the Conservative Party brand following its long period out of power.
He is credited with being the main architect of the government's 'Big Society' volunteerism agenda, which has frequently been criticised for failing to connect with the public.
His departure has been viewed by many Westminster watchers as a blow for Cameron, who is believed to rely heavily on his right hand man.
Hilton is known as something of an eccentric member of the Downing Street staff and is said to wander its corridors without wearing any shoes.
His wife Rachel Whetsone, is communication chief for Californian based internet giant Google.