Some say he didn't exist, some say he was a leader: the truth may never be known

Even if the full truth of the Stakeknife affair should ever be known, the vast clouds of suspicion that billow around the intelligence world mean many people probably would not recognise it.

Even if the full truth of the Stakeknife affair should ever be known, the vast clouds of suspicion that billow around the intelligence world mean many people probably would not recognise it.

The range of beliefs concerning Stakeknife is wide. Some think he was simply one army agent, important but not exceptional, in the IRA's ranks; some think he did not exist at all.

At the other end of the spectrum are those, who include disaffected republicans, who claim he has manipulated the entire republican movement and pulled it inside out.

They go so far as to allege that he is in reality the unacknowledged architect of republican policy and thus of the entire peace process.

In this world of smoke and mirrors, of fevered speculation and tabloid excess, it is difficult to sort out the information from the disinformation and exaggeration. But everything points to the fact that, contrary to some suggestions, Stakeknife does exist. A number of confidential sources assert this confidently, as apparently do some former disaffected intelligence agents.

The strongest evidence comes from the Metropolitan Police Commissioner, Sir John Stevens, who has publicly mentioned the agent's codename and said he expects to question him shortly. Sir John's work on the Finucane case and the question of collusion with loyalist paramilitaries, when he concluded that collusion existed and had cost lives, means he has a fair amount of credibility.

The suggestion that the IRA itself may have been promoting the Stakeknife story is regarded in Belfast as ludicrous. It is not known whether the IRA's leaders believe they know the full facts about the agent. But the grass roots of the IRA and the wider republican community certainly do not, and the affair has generated much confusion and controversy among people particularly prone to conspiracy theories.

The organisation is at a particularly delicate stage, since its ability to carry on with its traditional activities such as surveillance and training has become the primary focus of politics in Belfast.

There has already been much debate on whether the republican movement should accede to Tony Blair's demands for it to give an undertaking to desist from such activities.

The thought that military intelligence may have been manipulating the IRA itself though Stakeknife is a deeply unsettling one for republicans, making them wonder who has been in charge all these years.

Against such a troubled background it is unlikely that anything the IRA may say or do, and indeed that Freddie Scappaticci might assert, will satisfy everyone. The clouds of doubt and suspicion seem destined to become a permanent feature of the Belfast landscape.