Foreign Office claims 53-year-old spy chief's departure part of long-planned move and nothing to do with Edward Snowden revelations

The Foreign Office confirmed that the head of GCHQ, the British spy agency at the centre of the Edward Snowden leaks controversy, is to stand down.

The departure of Sir Iain Lobban, 53, who has been GCHQ director since July 2008, was being presented by the government as a long-planned move rather than being linked to the Snowden row.

The Foreign Office said: "Iain Lobban is doing an outstanding job as director GCHQ. Today is simply about starting the process of ensuring we have a suitable successor in place before he moves on as planned at the end of the year."

Lobban made a rare public appearance before a parliamentary committee in November at which he claimed the leaks to the Guardian had been damaging in the fight against terrorism. Lobban, who normally shirks publicity, was questioned by the parliamentary intelligence and security committee along with the heads of MI5 and MI6, Andrew Parker and Sir John Sawers. Lobban seemed to be the most uncomfortable of the trio with being in the limelight.

Commenting on his planned departure, the former Labour minister Lord Foulkes, a former member of committee, said: "I think he was doing a good job. He impressed when I was on the ISC. GCHQ is vital for national security and the recent publicity may have undermined this."

The leak of tens of thousands of top-secret documents by Snowden, the biggest breach of security since Kim Philby defected to Russia 50 years ago, has proved a major embarrassment for GCHQ and its American partner, the National Security Agency (NSA). The leaks raised questions about internal security and about the huge number of Americans, estimated at 850,000, with clearance to view such material.

Sir Iain's counterparts at the NSA, its head, General Keith Alexander, and his deputy, John Inglis, are also stepping down this year. There are calls too for America's director of national intelligence, James Clapper, to stand down for lying to Congress over the scale of data collection in the US.

Sir Iain, whose job is being advertised, is expected to remain in post until about the end of the year.

When the Treasury solicitor Sir Paul Jenkins retires in March, only Sir Nick Macpherson at the Treasury will have served longer as head of department than Lobban.

GCHQ operates a huge eavesdropping operation worldwide in partnership with the NSA and, to a lesser extent, Australian, Canadian and New Zealand surveillance agencies.

Lobban has more than 6,000 staff under him and GCHQ accounts for the bulk of the three intelligence agencies' combined budget of £2bn.

He has spent most of his working life at GCHQ, having joined in 1983. But the director does not necessarily have to be a lifer. Sir David Omand, who was director from 1996 to 1997, started at GCHQ but also worked at the Ministry of Defence.

Born in Nigeria in 1960, Lobban studied French and German at the University of Leeds. He routinely spends Tuesdays to Thursdays in London briefing ministers along with other duties with the rest of the working week spent at GCHQ in Cheltenham.

Lobban supports Everton football club, and declares his other interests as cricket, photography, travel and birdwatching.

During the committee hearing, he said that terrorist groups had discussed changing their communication methods in the light of the Snowden revelations.

He employed the haystack metaphor in denying that GCHQ invaded the privacy of innocent citizens. GCHQ was looking for needles and left the rest of the haystack untouched, he said.