Gerry Adams appears set to bow to pressure and fly to the US to give evidence to a Capitol Hill inquiry into links between IRA operatives and Colombian guerrilla groups.

The congressional hearing, which is unlikely to take place until after the Irish elections, comes as the IRA is facing fresh questions at home over the status of the IRA's ceasefire.

The one-time terror group has been linked to the burglary at the Castlereagh special branch unit and has come under fire over a "hitlist" of senior Tories.

Iain Duncan Smith met with the prime minister yesterday to seek reassurance that the dossier did not amount to a heightened risk to MPs.

Dr John Reid, the Northern Ireland secretary, insisted that the document did not threaten the IRA's ceasefire.

Government insiders have suggested that disgruntled special branch sources may be to blame for the recent spate of leaks about the IRA's alleged activities.

Tory peers yesterday strongly objected to plans to allow Sinn Fein's four MPs access to the Lords' corridors.