A FORMER MI5 and British army agent who infiltrated the republican movement in Derry has died.
Willie Carlin, who was aged in his 70s, is reported to have passed away earlier this month.
Mr Carlin, who also worked for the British army's Force Research Unit, published a book about his life in 2019.
'Thatcher’s Spy: My Life as an MI5 Agent Inside Sinn Féin' revealed how he infiltrated Sinn Féin during the 1970s and 1980s.
He was later exposed as an agent and forced to flee Derry.
It is understood that in recent years he had lived in the London area.
While working as an agent he provided information on Sinn Féin’s strategic political thinking and was close to key figures including Martin McGuinness, who died in 2017.
In his book Mr Carlin reported how he enjoyed a typical Derry childhood and revealed how he contemplated joining the priesthood as a teenager.
After leaving school at the age of 15 he worked in a factory in Derry.
In 1965 he and a brother joined the British Army's Queen’s Royal Irish Hussars and he was later stationed in Germany and England.
While still a serving soldier he got married and returned home to Derry in 1974 after agreeing to gather political intelligence for MI5.
In 1980 he severed links with MI5 after losing faith in his handler.
He contacted British military intelligence after the IRA killed census worker Joanne Mathers in April 1981.
In 1985 his life as an agent was eventually exposed forcing him and his family to flee their home city.
Academic Dr Aaron Edwards interviewed Mr Carlin for his 2021 book 'Agents of Influence: Britain’s Secret Intelligence War Against the IRA'.
Dr Edwards, who is a senior lecturer in defence and international affairs at the Royal Military Academy, Sandhurst, wrote this week that Mr Carlin died of complications arising from a Covid-19 infection on Monday February 6 and is survived by his wife and child from a second marriage.
"Willie quickly became a key component of the intelligence attack against the Provisionals, particularly in the wake of the hunger strikes," he said.
He said Mr Carlin's family connections with the republican movement and close association with Mr McGuinness "soon gave him a ringside seat in the secret intelligence war in Ireland".
"Through his long-term deception, Willie Carlin was partly responsible for setting the Provos on the path to political engagement that ultimately undermined their armed struggle and saw them embrace the ballot box," he said.
Dr Edwards said Mr Carlin may not have revealed everything he knew before his death.
"Suffice to say that while he may well have shared some secrets in his extensive interviews with me and in his autobiography, I always got the feeling he was prepared to carry many more to his grave," he said.
Mr Carlin's publisher Conor Graham said it was "fascinating experience working with Willie when I published the story of his extraordinary life".
"He was a real character who lived on his nerves but maintained the conviction of his beliefs right to the end," he said.