In the wake of the DUP leader's statement on the future governance of the country this week, and an interview he gave to Total Politics magazine explaining that his team of MPs were reluctant to give up their Westminster roles while Stormont's foundations (and therefore their seats) were not assured, UUP leader Sir Reg Empey posed the question: what has happened to DUP boasts of being the only party that had brought security to the institutions?

Having been goaded by DUP members that the days of crisis that characterised the Trimble years are over, Sir Reg said his party was entitled to highlight that its political rivals were now discovering that dealing with republicans was not as easy as they thought.

He pointed to a long list of DUP comments over the past year claiming that the DUP had sealed a new deal, a fair deal and a deal that would stick.

In the wake of a devolution deal with Sinn Fein in April 2007, Mr Robinson said: "Unionists now control their own future."

In May 2007, Ian Paisley Jnr said: "The days of Sinn Fein holding the process and the institutions to ransom are gone."

In May 2008, Nigel Dodds said: "Our policy of traditional common sense Unionism is delivering for our community – no one can with any credibility deny that is the case."

But to these, and other remarks he noted, Sir Reg said the DUP was failing because the deal with Sinn Fein was not delivering for the people – with government at a standstill and characterised by stagnation and deadlock.

The Ulster Unionist chief said that in light of what the DUP had been saying for a year, Mr Robinson's admission of a lack of stability was "an extraordinary statement".

"What happened to the stability, confidence and security which the DUP claimed to have brought to the institutions? What happened to the fairer, better deal?" he said.

"Mr Robinson's concerns about the stability of the Assembly are at total variance with what his colleagues have been saying over recent months. Indeed, putting it bluntly, he and his colleagues are clinging to their Westminster seats because they aren't convinced that they will have Assembly seats in a few months' time.

"That's hardly a firm foundation for the "unionist confidence" that the DUP has been spouting since St Andrews."