THERE will be an "informer's festival" next week in Rocky Sullivan's bar on Lexington Avenue, New York, to coincide with the US visit of Sean O'Callaghan. The crude language of the invitation to an evening of anti-O'Callaghan diatribe, which includes a showing of the John Ford film, The Informer, contrasts with the dignified, courteous passage through Washington this week of the man himself.

But it was always going to be the case that there would be a much hotter reception for O'Callaghan among the traditional republican groups in New York and Boston. Mr John Hurley, of the Friends of Irish Freedom group in Boston, went on a local radio show to say that an FBI agent concerned about O'Callaghan's safety asked that word be put "on the street not to kill Sean O'Callaghan".

The word on the street in more sedate Washington would have been more like: Sean who? In spite of efforts by the organisers of his tour to get O'Callaghan noticed by mainstream media, his exposure was largely on radio phone-in programmes.

At his opening press conference, there were almost more representatives of political organisations than journalists.

Claims by the organisers, who included the Sunday Times correspondent in Washington, James Adams, and London-based historian and columnist, Ruth Dudley Edwards, that O'Callaghan would meet editorial boards of major newspapers, the Senate Foreign Relations Committee and appear on high-profile TV shows like the McNeil-Lehrer Hour, all turned out to be wishful thinking.

The highlight of the Washington part of the tour was O'Callaghan's debate with the New York Republican Congressman, Mr Peter King, in a committee room on Capitol Hill. The debate was organised by the conservative weekly magazine, National Review.

O'Callaghan handled himself well in the debate in which Mr King tried hard to undermine his credibility, accusing him of being "either the Forrest Gump of Ireland or the Manchurian Candidate or both". In other words O'Callaghan was having fantasies or was on mind-bending drugs.

Mr King actually outlined the charge when he said O'Callaghan had been on anti-psychotic drugs in jail and had been reported eating light bulbs. O'Callaghan strongly denied both claims.

Mr King also read out a chilling account by O'Callaghan of how he shot dead another IRA informer, John Corcoran, in 1985. This murder has come up frequently during the visit. American Journalists were sent briefing material on it and other aspects of O'Callaghan's career by the Sinn Fein office in Washington.

When he is asked about it, he admits that he made a full confession to the RUC about this murder, as well as the two he committed in Northern Ireland after he walked into a British police station to give himself up in 1988. As far as he is concerned, he can still be arrested by the Garda for this unsolved murder.

One of the more curious aspects of the visit was O'Callaghan's willingness to testify as a hostile witness at the deportation hearing of former IRA man, Brian Pearson, from Clogher, Co Tyrone, whom he would presumably have known when he was an IRA operative in the area in the early 1970s. Pearson was convicted for an attack on the RUC barracks in Clogher.

The American lawyer and journalist, Mr Jonathan Stevenson, author of the recent book on Northern Ireland, We Wrecked the Place, has been advising the Immigration and Naturalisation Service for the Pearson hearing and he telephoned O'Callaghan to say the INS would like him to testify and so strengthen their case for Pearson's deportation.

When news of this was published in The Irish Times, the INS came under pressure in Washington, probably from the White House itself, to drop O'Callaghan, whose visa was specifically for a lecture tour and media appearances.

While the purpose of the O'Callaghan tour was to hammer home the message that there is no place for Sinn Fein in multi-party talks without an IRA ceasefire - the position of the US as well as the Irish and British governments - it was another thing to have him involved in a deportation case which is arousing strong feelings here and has Cardinal O'Connor of New York interceding for Pearson on humanitarian grounds.

But another part of the O'Callaghan message is not welcome to the US administration or to the Government and that is that the peace process is doomed if it is depending on Mr Gerry Adams and Mr Martin McGuinness to deliver an IRA ceasefire. O'Callaghan has been cleverly using Mr John Hume's recent denunciation of Sinn Fein electoral tactics to support his argument.

Based on his "experience of 16 to 17 years inside the republican movement", O'Callaghan is telling all who will listen in the US that those still hoping for a ceasefire "are going to be more disappointed with Gerry Adams than any other republican leader or spokesperson".