The MI5 agent whose single gamble helped to end the Troubles

On February 7 1991, an IRA mortar, fired from a white Ford Transit parked in Horse Guards Avenue at the junction with Whitehall, exploded on the Downing Street lawn in the middle of a Cabinet meeting. The Prime Minister, John Major, was told that, if the mortar had landed ten feet closer to the Cabinet Room, “half the Cabinet could have been killed”.

Remarkably, only two years later, on February 22 1993, Major received via an intelligence back-channel a message from the IRA, which marked the beginning of the long and tortuous path eventually leading to the Good Friday Agreement of 1998. This back-channel was to be crucial to the peace process.

Operation Chiffon concentrates on the two leading practitioners of the back-channel. Peter Taylor has had unique access to both. Brendan Duddy, a nationalist Derry businessman, first used as a secret point of contact between the IRA and Whitehall twenty years earlier, was in direct touch with the IRA leader Martin McGuinness. Taylor made contact with Duddy in 1998: “Into the small hours of the morning, over a bottle of Irish whiskey, he told me a story which could have come out of an airport thriller.” Duddy “put his life on the line for peace, narrowly surviving three terrifying IRA interrogations when he was suspected of being a British spy”.

Tracking down Duddy’s main back-channel contact in MI5, however, was much more difficult. Initially Peter Taylor knew only the contact’s given name, “Robert”. The first clue to Robert’s identity was a Latin quotation from Virgil’s Aeneid which Robert inscribed on a book he presented to Duddy. Taylor deduced that Robert had a classical education, possibly at Oxbridge. Since Robert had initially joined MI6 before working for MI5, it was also likely that he had worked under diplomatic cover in a British embassy abroad. Having worked out Robert’s approximate age, Taylor then asked his researcher to go through lengthy lists of examination results in Oxford and Cambridge, as well as diplomatic records in the BBC library. Having found Robert’s probable identity, the researcher also discovered his current address at a remote English farmhouse.

Taylor’s first meeting with Robert, over a decade after the Good Friday Agreement, took place in pouring rain:

To my surprise, at this point in the book I have a minor walk-on part. Robert later admitted that one of the reasons he kept Taylor standing outside his farmhouse in heavy rain, rather than allowing him inside, was to prevent him seeing on his bookshelf my centenary history of MI5, in which I describe the role in beginning the back-channel of Brendan Duddy – whom Robert claimed he had “never heard of”.

Years later, in 2021, Robert, by then in his late eighties, changed his mind. He contacted Taylor, confirming his identity and offering to provide “some background which might fill some gaps” in his research. “It was this encounter with Robert,” writes Taylor, “that, above all, led me to write this book. It is the final piece in the complex jigsaw of peace.” Robert revealed that he had told McGuinness and a leading Irish Republican, Gerry Kelly, in 1993: “The final solution is union. It is going to happen anyway... This island will be as one.” Robert also told Taylor that he had had no authority to make such a claim – in fact, it flew in the face of the Government’s policy. But it made a great impression on the IRA leadership.

The one significant gap in Peter Taylor’s gripping account of Chiffon, the secret MI5 operation designed to “achieve a ceasefire and talks” with the IRA, is the major change in Government counter-terrorist policy that made the operation possible. For most of the 20th century, British counter-terrorism was handicapped by the irrational division of intelligence responsibilities between MI5 and the police, which helped to make possible both the 1984 IRA bombing of the Grand Hotel in Brighton during the Conservative Party conference, and the 1991 mortar attack on Major’s Cabinet. Until 1992, the lead intelligence role against Irish Republican terrorism on mainland Britain belonged to the Met’s Special Branch, while the main responsibility for intelligence against loyalist paramilitaries and all non-Irish terrorists was assigned to MI5.

During Operation Ascribe in 1992, MI5 was finally given the lead intelligence role against all varieties of terrorism. For the remainder of the 20th century it operated primarily as a counter-terrorist rather than a counter-espionage agency – for the first time in its history.

Christopher Andrew is the official historian of the Security Service. Operation Chiffon : The Secret Story of MI5 and MI6 and the Road to Peace in Ireland by Peter Taylor is published by Bloomsbury at £22. To order your copy, call 0844 871 1514 or visit Telegraph Books