Northern Ireland's First Minister, Mr David Trimble, has said "a very serious problem" would arise for the peace process without progress on weapons inspections and decommissioning.
Speaking at a reception here attended by the Conservative Party leader, Mr William Hague, Mr Trimble warned the Northern Ireland Secretary, Mr Peter Mandelson, not to assume there was "no bottom line" for unionists.
He also criticised the Blair government, saying it had got itself into "the crazy position" of appearing to offer concessions to republicans to induce them to carry out promises already made on weapons inspections and on decommissioning.
Mr Trimble said Mr Mandelson might believe that further moves towards demilitarisation in south Armagh, and the abandonment of extradition proceedings against on-the-run terrorists, were unrelated to the weapons question. "But his belief is not relevant to this," he said.
"I'm absolutely certain that the republicans believe these actions were only taken because of their pressure. And not only do republicans believe that, I'm sure the greater number of people in Northern Ireland believe it."
Describing it as "a crazy position for any government to get itself into", Mr Trimble said: "What they should say to republicans is very simply: `You have given an unqualified promise, you carry out that promise, we will not do anything to induce you to carry out a promise you have made.' "
The IRA displayed outdated weapons when their arms dumps were inspected in June, according to a report in today's London Times.
Few details emerged about what the two international inspectors saw in the caches. The report quotes senior security sources as saying the weapons were "close to or beyond their sell-by date".