Others have been more fortunate. Sean O'Callaghan from Co Kerry was a senior republican leader in the 1980s with access to leading figures like Gerry Adams and Martin McGuinness. But O'Callaghan was working for the gardai. He wrote a bestselling memoir of his life as an informer but was forced to move to England.

Another alleged informer, Freddie Scappaticci, was 'outed' in May 2003. Scappaticci denied that he was the informer known as 'Stakeknife' but he was also forced to leave Northern Ireland.

Donaldson is, however, just the latest in a long line of people in Irish history who were punished for touting. During the War of Independence, Michael Collins organised a network of spies and informers to infiltrate and counter the activities of the British secret service operating from Dublin Castle.

Collins's men were brutal in their activities and shot dead some 80 spies.

In June 1942 there was the bizarre episode involving Stephen Hayes, the then chief of staff of the IRA, who was seized at his Dublin home and brought to an isolated cottage outside Dundalk, Co Louth. He was interrogated there before being moved to a house in Rathmines, Dublin. A court martial was held on 23 July which Hayes later recalled "was really a mixture between a schoolboy rag and an American gangster film".

The IRA man was found "guilty of treachery by having deliberately forwarded information, of a secret and confidential nature concerning the activities of the IRA, to a hostile body". But before he was to be shot dead, Hayes was forced to write a confession of his actions "to wreck the IRA". This went on until early in September when Hayes managed to escape and make his way to the garda station in Rathmines. He was subsequently given a five-year prison sentence for his involvement in the IRA while his captors were arrested when gardai raided the Rathmines house.