MR David Ervine of the Progressive Unionist Party has warned war would resume if the issue of decommissioning was tackled in isolation.

The Ulster Unionists, the Democratic Unionists and the UK Unionists want decommissioning made the subject of a special subcommittee meeting over the summer to produce a firm timetable for handing over arms during the substantive talks.

"I fear the atmosphere is so polluted in Northern Ireland, and there is such a fear of a resumption of serious violence, that any hope or opportunity of even engaging in discussion about decommissioning at this time by those who are purported to be the representatives of those with guns would be deeply debilitating," Mr Ervine told BBC Radio 4's World at One.

"One, I absolutely cannot at this time deliver, and two, it would be a destabilising factor on the paramilitaries themselves to have negotiations going on which were about weaponry rather than about the cause of the conflict."

He painted a bleak picture of what he feared would happen if those three parties did not rethink their position.

"My fear, my analysis, is that the talks will adjourn without a proper discussion on decommissioning. We will probably have a resumption of IRA violence, in a more serious way than it already is, and they would be followed back to war by the loyalists.

He stressed: "My analysis is only an analysis. I'm not threatening or sabre rattling."