UK Unionist leader BOB MCCARTNEY stood aside to allow the DUP a clearer run in the 2005 General Election, after the DUP assured him there was "no question" of it entering a D'Hondt-style coalition government with Sinn Fein. However, last week DUP MP Peter Robinson said his party may accept D'Hondt for a limited period. Today, Mr McCartney warns that many unionists will never trust the DUP again if it breaches this manifesto pledge.

Wednesday, I was accosted by an irate lorry driver on a filling station forecourt. Waving a copy of the News Letter; he demanded to know "what are the DUP playing at?".

His anxiety, which many thousands of unionists will share, was caused by Peter Robinson's suggestion that, in exceptional circumstances, an enforced coalition with Sinn Fein under D'Hondt might be accepted, for a strictly limited period, to get devolution off the ground. This limited period is believed to be for no more than four years.

The overwhelming vote of confidence which the DUP received in June 2005 was on the basis of the electorate's rejection of the Government's concessions to Sinn Fein and the guaranteed places which that party would get in government under the D'Hondt arrangement. The electorate's perception of the DUP's total opposition to Sinn Fein in government, was confirmed by its 2005 manifesto which categorically stated that enforced coalition with Sinn Fein under the terms of D'Hondt or any other such arrangement was out of the question for the foreseeable future. Indeed, I stood aside for a DUP candidate in North Down on the basis of a personal assurance to that effect from the DUP leadership.

The electoral meltdown of the Ulster Unionist Party in 2005 was largely due to its pursuit of a devolution policy under the terms of the Belfast Agreement which included guaranteed ministries for Sinn Fein under D'Hondt. The electorate put their trust in the DUP on the basis of manifesto commitments that it would not to do likewise. Many unionists inside and outside the DUP will view Mr Robinson's suggestions as a breach of those assurances.

For years, successive British Governments have waited for the day when the DUP's ambition for power would overcome its declared aversion for Sinn Fein as coalition partners. Many unionists will fear that the dawn of that particular day may now be about to break.

The DUP should remember that only two players in Northern Ireland politics have a clear strategic objective. The British Government, which wants disengagement from Northern Ireland, and Sinn Fein which wants Irish unity. Both of these goals are entirely consistent with each other. Both objectives require the outflanking of the unionist road block, and enforced coalition under D'Hondt in a devolved Assembly is the preferred route to their achievement.

DUP acceptance of Sinn Fein as partners in government on whatever terms would give an enormous boost to Sinn Fein in the Republic's 2007 elections. Indeed, as Pat Doherty recently claimed, the prospect of Sinn Fein ministers, North and South, in cross border bodies remains more than a possibility. The impetus that this would give to the concept of a united Ireland would be massive as unionist encirclement would be a prelude to its surrender.

Many DUP members may well view a U-turn on the manifesto promises as a betrayal of the electorate's trust and a massive blow to their faith in the integrity of Ian Paisley's leadership. Many others will question if he is fully aware of the strategic implications of the ideas now being floated.

The mechanisms for gaining what would be a "claimed" grassroots approval appear to have been carefully worked out already, with a party consultation reminiscent of David Trimble's routine and a chronology of events so refined as to indicate careful planning.

The DUP will not enter into an Agreement before November 24.But a deal, which it has reason to believe will be acceptable to the two governments and Sinn Fein, will be crafted. This will, of necessity, include enforced D'Hondt power sharing with Sinn Fein.

Then the prepared package will be heavily sold in the consultation process with unionists, though - unsurprisingly -its results will be assessed by party officers themselves, who will make the final decision. And there will be a lurking suspicion that the DUP leadership may well, like David Trimble in similar circumstances, only hear what it wishes to hear.

Since the 2005 manifesto is an obstacle to this whole scenario, an election sometime in 2007 will be necessary. A fresh manifesto will include terms that will permit the DUP to enter government with Sinn Fein under D'Hondt or a similar arrangement. The DUP will claim that it has forced Sinn Fein to accept in full the democratic process and has secured safeguards that it will continue to do so.

Sinn Fein will assert that it has forced the DUP to acknowledge its legitimate right to govern. In many cases, the personal ambitions and interests of some will have triumphed over principle and integrity. The question is - will the unionist electorate ever forgive or trust them again?