DUP deputy leader Peter Robinson has suggested that power-sharing with Sinn Féin could be off the unionist political agenda for a generation.
At the same time he and other senior party sources are predicting a DUP victory over the Ulster Unionist Party by at least 9 seats to 2 in the British general election expected on May 5th.
Mr Robinson was speaking to The Irish Times ahead of publication next week of a new DUP policy document entitled Moving On.
In it the DUP will press the case for a voluntary coalition of unionists and nationalists to resume devolved government at Stormont without Sinn Féin.
Mr Robinson said the failed negotiation of last December had persuaded the DUP that Sinn Féin "was not capable of making the transition to peace and democracy".
He continued: "We believe the best option is voluntary coalition and it is in that direction that we will now deploy our efforts."
Reminded that it remained the declared policy of both the British and Irish governments to restore a fully "inclusive" power-sharing Executive, Mr Robinson replied: "We don't believe they (Sinn Féin) will make the transition, so it's no longer in our reckoning. We're saying that that era is past and gone."
Ulster Unionist leader David Trimble told his party's annual meeting earlier this month that he did not "intend" to rejoin a partnership government with Sinn Féin, while stopping short of saying "never".
Pressed to say whether he ruled out an inclusive government with Sinn Féin even if republicans eventually met the standards required by the two governments, Mr Robinson declared: "If they (republicans) reform at a later stage that's a matter for the next generation to look at."
This pre-election hardening of the DUP's position was underlined in the Commons yesterday when Andrew Hunter, the former Conservative MP who now takes the DUP whip, told Northern Secretary Paul Murphy that "inclusivity is no longer on the agenda".
During Northern Ireland Questions, Mr Murphy repeated that the British government's ultimate goal remained the restoration of an inclusive Executive at Stormont.
Mr Murphy accepted that the prospect of an Executive as envisaged by the Belfast Agreement was "unrealistic at the moment". He reiterated his belief that the majority of people in Northern Ireland wanted government to resolve the issue of republican criminality of the kind which had resulted in the Northern Bank robbery and the murder of Robert McCartney.
However, Mr Murphy also found himself under renewed pressure to address what Conservative spokesman David Lidington called the "profound democratic deficit in direct rule" by Westminster. And Mr Murphy was again challenged by Mr Trimble to bring forward the necessary legislation to scrap the existing procedure for appointing an Executive at Stormont, thus enabling "the other parties" to move ahead without Sinn Féin.
Mr Murphy told Mr Trimble he was "more than happy" to consider the alternative proposals put forward by the political parties, while stressing it would be "impossible" to find an alternative way forward even as a temporary measure "unless the parties (both unionist parties and the SDLP) agree to work together."
Pressed by Mr Lidington on whether Downing Street was engaged in continuing discussions with Sinn Féin, Mr Murphy suggested the government had "a single-issue agenda" for any such talks - namely securing an end to IRA paramilitary and criminal activity.
Private polling has apparently increased DUP confidence that it can defeat Mr Trimble in his Upper Bann constituency in the forthcoming election.