The new director general of the UK's security intelligence service, MI5, is a former Fairy Godmother who once taught Nigella Lawson. BBC News Online pieces together the secret life and times of Eliza Manningham-Buller.

Andrew Walker BBC News profiles unit

During the early 1980s, only five people knew that Oleg Gordievsky, the deputy head of the KGB at the Soviet embassy in London, was actually a double agent. One of this exclusive group was MI5's senior officer dealing with Soviet affairs, Eliza Manningham-Buller.

As Gordievsky recently acknowledged, Manningham-Buller's ability to keep a secret saved his life.

Despite the fact that two of her assistants shared an office with Michael Bettany, a traitor working for the KGB, Gordievsky's crucial role was never mentioned.

One word in front of Bettany, who recently completed an 18 year sentence for spying for the Soviets, and Gordievsky would have been on the first plane to Moscow and an inevitable date with an executioner's bullet.

Manningham-Buller saved Gordievsky

Gordievsky says that her appointment is "the best news for the service in a decade."

Born in 1948, the Honourable Elizabeth Lydia Manningham-Buller's refined background is clear for all to see.

He father, Sir Reginald (later Lord Dilhorne), served as Attorney General and Lord Chancellor in the Conservative administrations of Harold Macmillan and Sir Alec Douglas-Home.

Pantomime

In 1961, as attorney general, he played a crucial role in exposing the traitor George Blake, by allowing MI6 officers to interrogate Blake.

"Just make sure you bring him back alive," he quipped at the time. They did, but only after Blake had confessed.

A contemporary of Princess Anne at the exclusive girls' public school, Benenden, Eliza Manningham-Buller's forthright character brought her the nickname "Bullying Manner".

Eliza is a highly intelligent, very experienced and very kind person

Dame Stella Rimington

She read English at Lady Margaret Hall, Oxford, where it is believed MI5 first attempted to recruit her, much to her father's distress.

While at Oxford, she starred as the Fairy Godmother in a production of Cinderella directed by Giles Brandreth.

After graduating, she worked as a teacher at the swanky Queen's Gate school in London. Among her pupils there was the future journalist and cookery writer, Nigella Lawson.

Former pupil, Nigella Lawson

But, after three years, she finally joined MI5. It was 1974, the Cold War was at its frostiest and Eliza Manningham-Buller soon progressed form typing up transcripts of tapped telephone conversations between Warsaw Pact diplomats to becoming a fully-fledged spycatcher.

Unlike her predecessor as director general, Dame Stella Rimington, Eliza Manningham-Buller has vast experience as an operational intelligence officer.

An expert on counter-terrorism, she was heavily involved in the Lockerbie investigation, served as MI5's liaison officer in Washington and became director of the agency's Irish counter-terrorism branch, spearheading the fight against the Provisional IRA.

The best news for the service in a decade

Oleg Gordievsky on MI5's new head

Since 1997, when she was appointed MI5's deputy director general, Eliza Manningham-Buller has had responsibility for the organisation's day-to-day work and its relations with other agencies, both at home and abroad.

Dame Stella has welcomed her successor's appointment. "Eliza is a highly intelligent, very experienced and very kind person", she says.

But she has this warning, "the media will focus on what she looks like and what clothes she wears because she's a woman."

But critics say that her accession to the top job simply reveals the deeply conservative nature of the agency and its unwillingness to countenance modernisation.

MI5: defending the realm

On the domestic front, Eliza Manningham-Buller lives in Bath with her husband, David, whom she married in 1991, and his five children from an earlier marriage. Despite the pressures of her job, she is still said to cook a roast Sunday dinner for her family every week.

Today, her professional life is dominated by the fight against al-Qaeda. She flew to Washington on 12 September 2001 to liase with her counterparts in the CIA and FBI and is recently said to have told Tony Blair that he is on an al-Qaeda hit-list.

But, for every fact we do know of Eliza Manningham-Buller's life, there are probably a thousand other secrets, revealed only to the clandestine warriors at MI5's headquarters at Thames House in London.