Sir John Sawers named new MI6 chief

File photo of John Sawers at the United Nations headquarters, in New York, April 13, 2009.

LONDON (Reuters) - The government named high-profile ambassador John Sawers on Tuesday as the new head of its Secret Intelligence Service (SIS), also known as MI6, saying he was rejoining the espionage agency after years as a diplomat.

Prime Minister Gordon Brown's spokesman said Sawers -- the ambassador to the United Nations -- would take up the post in November when incumbent John Scarlett is due to retire.

Sawers is a former ambassador to Egypt and Foreign Office political director. He was an SIS member early in his career and was now rejoining it, an official said.

As Foreign Office political director Sawers was "closely involved in policy on Iran, Iraq, Afghanistan and the Balkans," according to the website of the British mission to the United Nations. He has also worked in Yemen, Syria and South Africa and was involved in peace efforts in Northern Ireland.

Foreign Secretary David Miliband welcomed the appointment.

"International terrorism, proliferation of weapons of mass destruction and the growth of regional conflict and instability mean that there has never been a time when the skills and dedication of our intelligence agencies, including SIS, have been more necessary to our national security and the safety of our people around the world," he said in a statement.

Scarlett has headed the service since 2004, after serving a controversial term as head of the Joint Intelligence Committee, which assembles information from several intelligence arms.

A probe into intelligence before the 2003 Iraq invasion criticised Scarlett for putting his name as JIC head on a dossier that then Prime Minister Tony Blair used to justify war.

The dossier made the intelligence appear stronger than it was, and the seal of approval from Scarlett's JIC made it worse, the chairman of the official inquiry, Lord Butler, concluded.

But Butler also said the error was not a sacking offence, and he cleared Scarlett to accept the promotion as head of SIS.

Under the system designed to shield spies from politicians, the various secret services report to the JIC, an arm of the civil service, which in turn advises the government.

Lord Carlile, the independent reviewer of terrorism legislation, told a conference in May that the Iraq dossier affair had affected trust in British intelligence.

Scarlett is expected to be among senior serving and former officials who will give evidence to another probe into Britain's decision to join the 2003 invasion.

Prime Minister Gordon Brown announced the long-awaited probe on Monday but said the hearings would be in private, citing national security concerns. Opponents accused him of a cover-up by refusing to hold the inquiry in public.

Britain sent 45,000 troops to join the U.S. invasion to oust Iraqi President Saddam Hussein on the grounds he was hiding weapons of mass destruction, which were never found.