A senior member of the IRA was secretly spying for the British army for the past 25 years, it has been revealed.

Alfredo Scappaticci, deputy head of the IRA's internal security unit, is reported to have provided crucial information to the army's Force Research Unit in return for £80,000 a year.

Scappaticci, who was outed on websites and in a number of Irish Sunday newspapers, is now in a safe house in England.

An IRA source told today's Guardian: "So many things are now falling into place, people who got whacked [killed] and we weren't sure why, things that happened that didn't make sense at the time."

The Northern Ireland Office, the army and Sinn Fein all refused to comment last night.