It has been a strange month in the politics of Northern Ireland, and last week was no exception. On Monday, there was optimism that a breakthrough on the devolution of policing and justice was in the offing. A few days later, talks had collapsed amid recriminations between Gerry Adams and Peter Robinson. UUP leader Reg Empey was predicting an assembly election would be called by the end of the coming week, a good indicator of the likely timeframe before a definitive breakthrough or breakdown.

Over-shadowing the week's events was a remarkable scoop from Slugger O'Toole's Eamonn Mallie, the veteran journalist who first revealed the British Government's talks with the IRA in the early 1990s. He reported that last Sunday, the DUP and Ulster Unionist leadership took part in secret talks in England with Shadow Northern Ireland Secretary Owen Paterson aimed at "unionist unity and copper fastening maximum unionist support for a future Conservative government, should there be a hung parliament."

The Conservatives denied that any discussion of a hung parliament had taken place, stating:

What this was, was the shadow Secretary of State as somebody who could potentially be the actual Secretary of State in a matter of weeks, holding private talks with representatives of the two main unionist parties to explore how we might overcome some of the political instabilities at Stormont, and to avoid a situation in which we might potentially, should we win the election, inherit a collapsed Assembly and direct rule.

On the face of it, this makes sense, particularly as the DUP would want political cover from the Tories' Ulster Unionist allies in the event of a deal with Sinn Féin. However, a series of intriguing stories undermined this picture. The Belfast Telegraph reported that the DUP was considering giving the Ulster Unionists a free run in two nationalist-held Westminster seats. RTE reported that Robinson was considering an outright alliance between the two parties, and the BBC reported that three Consevative parliamentary candidates had resigned.

The BBC's Mark Devenport summed up the situation at the end of the week:

When questioned about the prospect of Sinn Fein becoming Stormont's largest party, neither unionist leader would rule out their respective parties merging into one bloc. Although the Conservatives claimed there was no discussion of a hung Westminster parliament during the secret talks in England last Sunday, senior DUP sources are talking up the significance a single unionist force could have for the parliamentary arithmetic at Westminster. They are pointing out that 12 pro-Conservative seats equals 24 in a balanced parliament...of course that presumes both North Down and Fermanagh South Tyrone could be counted in such a bloc which is a big assumption. Nevertheless it gives a sense of the kind of calculations now being made.

The location of the talks may be significant: Hatfield House, the ancestral seat of Lord Salisbury, who as Viscount Cranborne was the key ally of Ulster Unionism in John Major's cabinet. His home has hosted a unionist unity conference once before. The UUP and DUP were both represented at this gathering which took place a few months after the election of Tony Blair in 1997. It was ostensibly organised at the initiative of Sean O'Callaghan, a former Provisional IRA member who became an advisor to David Trimble. Another member of Trimble's inner circle, the journalist Eoghan Harris, declined to attend because, in the words of Dean Godson, the event "had too much of the air of 1912-style resistance to Home Rule, with Unionists coalescing with what he saw as reactionary elements on the mainland."

Those words found something of an echo this week from SDLP Deputy Leader Alasdair McDonnell, whose South Belfast constituency is the most vulnerable to a pan-unionist alliance. He accused David Cameron of orchestrating "a cynical attempt by the Tories to grab a few orange votes ahead of the forthcoming Westminster election”.     

There may in fact be a case for a unionist realignment if it unites pro-agreement forces against the Traditional Unionist Voice. If however, it emboldens the DUP to risk the collapse of power-sharing, it will only serve the TUV's agenda. That would attract an extremely negative reaction from nationalists of all shades. It would also raise profound questions for all strands of unionism.

The DUP has spent forty years building at the expense of traditional 'big house unionism.' How will its electorate take to becoming pawns on a chessboard at the home of a Tory grandee?

The Ulster Unionists and the Conservatives have spent months talking up their alliance as the beginning of a new non-sectarian unionism that can attract Catholic voters. If even their own candidates no longer have confidence in that agenda, why should anyone else?

David Cameron believes he is on the verge of winning broad support from the British people as the responsible choice to lead the next Government. So why is he engaging in what looks uncomfortably like an opportunist manoeuvre for a dozen or so seats?