Fifty Dead Men Walking

For more than four years, Martin McGartland lived the double life of a secret agent.

To the IRA, he was a trusted Intelligence Officer and member of an active service unit.

To the British government he was "Agent Carol". By night, McGartland would be planning bombings and shootings of innocent people with the IRA.

Within hours he would have passed on the details to intelligence chiefs.

When his cover was blown, he was taken from Sinn Fein headquarters in Belfast to an IRA safehouse for questioning and almost certain execution.

Though guarded by three armed men, McGartland dived from a third floor window in a desperate bid for freedom.

McGartland is credited by British Intelligence with saving the lives of 50 people, and he now lives under a false indentity at a secret location in Britain.

This is his story.