What does MI6 do?

The Secret Intelligence Service likes to keep a low profile

MI6 is once again in the headlines. But what does it actually do?

Just one of Britain's secret intelligence agencies, MI6 is primarily concerned with information gathering outside the UK.

Established in 1912, the agency was known in full as Military Intelligence, section six, and did not officially exist for many years.

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This meant that for the best part of a century ministers did not have to answer questions about it in Parliament.

However, following pressure to make the service accountable, the then prime minister, John Major, changed its existence from an open secret into an accepted part of state machinery with the Intelligence Services Act of 1994.

Since the end of the Cold War, its axis has shifted away from the "Soviet threat" to the fight against terrorist groups and organised crime, such as drug-smuggling cartels.

New role

Now officially known as the Secret Intelligence Service (SIS) - despite still going by its misleading "military" intelligence name - its role is to gather information to aid the government's security, defence, foreign and economic policies.

Lord Justice Stuart-Smith, the outgoing Intelligence Services Commissioner, has said the SIS plays a particularly vital role in safeguarding the UK's economic wellbeing.

Spying does not stop at military intelligence

While this includes keeping tabs on the nations which supply us with vital raw materials, such as oil, its is suggested the SIS also take a keen interest in the activities of the UK's close economic allies.

A former member of the intelligence community told BBC News Online that while the service denies involving itself in so-called "industrial espionage" - the activity fits within the service's remit.

To gather its information, the SIS relies on a network of its own officers working abroad, as well as recruiting foreign nationals it deems useful.

Working abroad

This recruitment may even extend to those romantically involved with figures privy to the kinds of information the SIS seeks. Foreign recruits receive money or other favours for their efforts.

The Intelligence Services Act does not demand that SIS limit itself to merely observing foreign affairs. The act states that with prior permission the service can perform covert operations abroad which would be unlawful in the UK.

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Suggestions by former MI5 officer David Shayler that the SIS was behind a plot to assassinate Colonel Gaddafi, have been vigorously dismissed by Robin Cook, the foreign secretary.

However, author Stephen Dorril alleged in his recent book, MI6: Fifty Years of Special Operations, that SIS maintains a formidable array of military hardware on standby.

Clues as to extent of SIS's activities are difficult to come by. Mr Dorril has suggested the service's actual annual budget was double the £170m officially stated. There was considerable debate over whether to disclose the final cost of refurbishment to MI6's headquarters on the Thames.

SIS on the QT

It is often argued that the service acts in this "discreet" fashion to maintain its operational effectiveness. However there continue to be calls for the service to reappraise its deeply ingrained culture of secrecy.

In 1922, MI6's bureau chief Sir Mansfield Cumming took to signing himself "C".

While the heads of MI5 have came out of the shadows in the 1990s, Cumming's successors are still known as "C", a custom which echoes the service's strenuous efforts to protect the identities of its officers.

Richard Tomlinson threatened to lift the lid on MI6

This cloak of secrecy faced a serious threat last year when a renegade officer, Richard Tomlinson, threatened to post the names of a number of British spies on the internet.

The government suspect he made good this threat and was behind the naming of 117 MI6 officers on the web.

The Tomlinson affair, and the recent terrorist attack on its Vauxhall Cross HQ, have kept SIS in the headlines and given it the very thing its officers dread, publicity.