Raymond Gilmour infiltrated the IRA as a spy for MI5, the British Secret Service, during the Troubles in Northern Ireland. Now living under a false identity and suffering from mental health issues, the Irish Catholic supergrass claims he has been abandoned.

The former supergrass is now taking his complaint to the Powers Tribunal (IPT) and will launch a case against the British Secret Service.

Now 53-years-old, Gilmour lives in the southeast of England under a false identity. He says he is unable to work and also suffers from mental health issues.

Gilmour was the sole witness in the trial of 35 Irish Republican Army suspects in 1984. Gilmour now lives in constant fear of being killed.

Originally from Country Derry, Gilmour has been living under a false identity for his own protection for 30 years.

The informant told the BBC that the MI5 promised him $800,000 (£500,000), a new home, psychiatric support, and a pension. He said for three years he was provided with $950 (£600) per month. However, he was not provided with a job. He also said that his new identity does not stand up to scrutiny.

Gilmour is now unable to work and suffers from mental illness. He is an alcoholic and suffers from post-traumatic stress disorder (PTSD).

He told the BBC, “I brought the INLA to their knees in Derry, I brought the IRA to their knees in Derry and I saved countless lives.

"If I'm being treated like this after so many years, what do you think people down the chain are being treated like?

"I am living on a knife edge because of my mental health, I have no financial stability, which I was promised - I have nothing."

Through his Tory Member of British Parliament (MP), Gilmour is taking his case to the Investigatory Powers Tribunal (IPT), the organization that examines complaints against the intelligence services.

Gilmour was 17-years-old when he joined the Irish National Liberation Army (INLA) in 1976 as a Royal Ulster Constabulary (RUC) special branch agent.

In 1980 he moved to the Irish Republican Army before his cover was blown two years later. The police used the information he provided to recover a machine gun.

After Gilmore testified, 35 republicans in Derry were arrested. However, the case collapsed after the Lord Chief Justice dismissed Gilmour’s evidence.

Gilmour is “heartbroken and disgusted” by the judge’s comments.

He said, “I knew I was telling the truth, I was told there were deals struck by RUC men behind the scenes that decisions had to be made that wouldn't be palatable for me, so I was going to be the fall guy.”

For many, Gilmour is still remembered as a traitor. Former Sinn Fein publicity director Danny Morrison said, "There will be no love lost for him, no sympathy for him and it doesn't come unexpected that when MI5 are finished with people they discard them.”

Ian Paisley Jr, the Democratic Unionist Party MP for North Antrim, said he had sympathy for agents who had risked their lives and the government had failed to protect him.

He said, “An agent - that's who we're talking about - who worked for the government in the dirtiest war ever this side of Kosovo should be protected and given his contractual obligations.”