In a key speech, which will be picked over in detail by republicans, and in London and Dublin, the DUP leader said those who thought his party was opposed to the transfer of law and order powers from Westminster "just don't get it".

Unionists, he argued, had historically demanded local control of policing responsibility.

And, he insisted, it was "a (DUP] manifesto commitment and a unionist ideal" to see this happen.

But, as he edged forward his supporters, the wider unionist community and the political process, he stressed once more that only when "essential conditions have been met" and "public confidence" is there, will the devolution of the powers actually occur.

"We will not be pushed or bullied on this matter," he said. "Our terms are unalterable."

The First Minister was addressing a dinner in Fermanagh, where DUP members were in celebratory mood, after the Enniskillen by-election victory of Arlene Foster.

He was speaking, too, ahead of what looks increasingly like a crucial week for the survival of devolution.

His party and Sinn Fein need to find a way through their current deadlock before a scheduled Executive meeting next Thursday and a North-South Ministerial Council meeting the following day.

After republicans agreed not to block Northern Ireland ministers participating in a British-Irish Council meeting in Scotland yesterday, the Robinson speech had the look of a choreography emerging.

A reciprocal gesture – albeit just the slightest of steps.

He sent a message to republicanism – of "we do want to do the policing deal" – which eased the tension around talks.

But he also had words of assurance for uncertain unionists.

"We will take our decision based on content, not the calendar," he said.

Crucially, though, he underlined. "We want devolution to take place, and it will. Those who believe the DUP does not favour any form of policing and justice devolution just don't get it," he said.

"It was our great unionist forefathers who first argued to get these powers into Stormont and a later generation of unionists who opposed them being removed. I want to see the return of policing and justice functions to Stormont – but, importantly, and as our manifesto clearly states, providing such powers are not placed in the hands of any Sinn Fein minister.

"But only when the essential conditions have been met. The other key condition for us is attaining support and confidence from the community in the structures and in those who will operate them."

In a signal that he may be gearing up for an internal unionist debate – the party has spoken of consulting its grassroots before any decision – Mr Robinson also said "there are many misconceptions about what the devolution of policing and justice actually means".

These range from who the minister would be right through to what powers the minister would actually have, he said.

"That is why we must ensure all the outstanding issues are satisfactorily resolved," he added – presumably in order to have the internal argument based on concrete facts.

"Our 2007 election manifesto made it very clear that the DUP would not support a Sinn Fein minister exercising control over policing and justice functions in the foreseeable future. A justice minister must be able to command widespread community support," he said.

In a week where Secretary of State Shaun Woodward reset his sights by speaking of devolving policing powers within 12 months, the First Minister made no suggestion he was suddenly rushing to sign up to Sinn Fein's biggest wish.

But he said his party has already made strides in "agreeing the context for devolution" – having settled on a single justice ministry for instance.

If the process is now to move forward he called for the blockade of the Executive to be lifted because "I do not respond well to threats".

And he told Sinn Fein its "harmful obstruction of Executive business is eroding confidence", so it would be better to restore good governance to the Province rather than languishing in stalemate.

Finally, to unionists, he urged them to be confident.

And he highlighted Gordon Brown's recent appearance at Stormont as a warning that the collapse of the institutions and a return to direct rule was not in their interests.

He said the Prime Minister came "riding over the hill to parrot Sinn Fein policy and implement a republican agenda". "Direct rule is Dublin rule," he said.