Peter Robinson's relations with former prime minister Tony Blair hit rock bottom in a fire alert at Parliament Buildings in Belfast, he has revealed.
The Democratic Unionist Party (DUP) First Minister met the Labour leader at Stormont as talks heated up on devolution in 2004.
He said: "We met in Parliament Buildings but unfortunately while Tony was seeking to convince us of his good and honourable intentions, the building's fire alarm went off." Mr Blair asked: "What's that?". Mr Robinson quipped: "It is the lie detector."
He reflected: "I think that indicates the level of trust that then existed between us."
The East Belfast Northern Ireland Assembly member said the prime minister had visited Belfast in an attempt to prop up former Ulster Unionist Party (UUP) leader David Trimble amid political negotiations over power-sharing.
The First Minister told an audience at the Institute of Irish Studies in Liverpool that at the start of 2004 Mr Blair was far from convinced that a deal with the DUP could be done, following elections in late 2003 which produced a strong DUP vote.
"I recall a meeting in Downing Street where I suggested that the DUP victory the previous November would turn out to be a blessing in disguise," the DUP leader said.
Mr Blair said: "If it was, then it was very well disguised."
In a revealing aside, Mr Robinson recalled how the DUP's reputation for having a hardline support base was useful during negotiations.
He said: "These factors for the most part, and for most people, were not accurate, but at times this perception about our position was not necessarily unhelpful in dealing with the Government, and we recognised that by not seeking to refute or indeed even, at times, accentuating our difficulties, we were able to rebalance the negotiating scales which had until then been weighed heavily in Sinn Fein's favour."