The Democratic Unionist Party (DUP) and the Ulster Unionist Party (UUP) have agreed to field one unity candidate in each of four general election constituencies in one of the most far-reaching eve-of-poll pacts for decades.
East Belfast, North Belfast, and the border constituencies of Newry and Armagh and Fermanagh and South Tyrone will be covered.
Party strategists aim to increase the number of unionists at Westminster with the odds of a hung Parliament and increased influence for the smaller parties high.
DUP leader Peter Robinson said: “This is the most comprehensive electoral agreement between our two parties in the last 29 years.”
For months most experts have been predicting that not only will neither the Conservatives nor Labour be able to command an overall majority in the Commons or form a coalition with one of the smaller parties - it appears that one or other of them will have to assemble some form of patchwork alliance involving multiple parties, or run as a minority administration with no guarantee it can get its business through the House.
The DUP, the largest Northern Ireland party represented in the Commons, has said it will support a government in a hung parliament if there is agreement to scrap the so-called bedroom tax, commitments on defence spending and securing UK borders.
Unionists face a challenge at the polls from Jim Allister’s hardline Traditional Unionist Voice, which opposes Sinn Fein’s inclusion in powersharing at Stormont. Ukip is to run a series of candidates in Northern Ireland which may also erode the mainstream unionist vote.
In East Belfast the DUP and UUP will encourage support for Gavin Robinson, a former Belfast City Council Lord Mayor.
Peter Robinson lost his seat in the last election to Alliance’s Naomi Long by around 1,500 votes.
In Fermanagh & South Tyrone both parties will encourage support for senior Ulster Unionist Tom Elliott. Sinn Fein’s Michelle Gildernew took the seat by a mere four votes last time after another unionist unity candidate ran against her.
In North Belfast both parties will encourage support for incumbent Nigel Dodds, deputy leader of the DUP.
In 2010 in North Belfast Mr Dodds polled 14,812 votes, with Sinn Fein’s Gerry Kelly on 12,588.
In Newry & Armagh both parties will encourage support for Ulster Unionist Danny Kennedy, Stormont’s regional development minister. The incumbent is Sinn Fein’s Conor Murphy.
Mr Robinson added: “Those who support the Union will recognise the significance of this pact.”
It is the product of discussions lasting six months.
“I want to see unionists co-operating. Too often divisions are manufactured to create difference. Grassroots unionists want to see us working together to maximise the unionist vote.
“Such an approach is not just desirable, but it has been proven to be effective in increasing turnout amongst unionists.
“With a predicted hung parliament, I am calling on all unionists to unite behind these agreed candidates and maximise the pro-union voice in the House of Commons.”
Sinn Fein MPs do not take their seats.
Mr Robinson claimed: “They leave their constituents without a voice in Parliament. Others do not represent unionism.
“All shades of unionism can lend their vote to these agreed candidates in the knowledge that their action could increase the number of unionists in the House of Commons and reduce the number of non-unionists returned.”
He said it had not been possible to include the constituencies of Upper Bann and South Belfast in the pact.
Nationalist SDLP leader Dr Alasdair McDonnell is the incumbent in South Belfast while the DUP’s David Simpson holds Upper Bann.
UUP leader Mike Nesbitt said: “We began these discussions in October proposing an anti-abstentionist arrangement for Fermanagh & South Tyrone and North Belfast (against Sinn Fein).
“Since then it has become clear that there is potentially a once in a lifetime opportunity to take back Newry & Armagh, albeit this will be extremely difficult to achieve. Our support for the DUP in East Belfast should ensure an additional pro-Union MP for the city of Belfast in the next mandate.”
In the event of a hung parliament, the first leader either David Cameron or Ed Miliband turns to may well once again be Nick Clegg - assuming he survives.
The Liberal Democrat leader has said he would seek to work with whichever party has the strongest electoral mandate after May 7.
However, if the polls are right, the Lib Dems’ own electoral mandate could well be severely diminished, with the party widely expected to lose so many seats it may well be unable to combine with either Labour or the Conservatives to secure an outright majority.
Speaking in response to the news, East Belfast Alliance MP Naomi Long said: “This is a pact that was sealed in East Belfast with 40,000 bogus leaflets. The DUP clearly now know that Gavin Robinson cannot win against Alliance in a fair fight, so they have resorted to this anti-democratic move in a desperate attempt to strengthen their position.
“Many UUP voters were already disillusioned by the party’s involvement in whipping up sectarian tensions around flags and parades and this decision will only serve to further alienate them. This decision has sounded the death knell for the UUP in East Belfast, who have abandoned their voters without gaining any truly winnable seats in return. It has also confirmed what has long been the case – if you vote UUP in East Belfast, you get the DUP.
“People already viewed the seat as a two-horse race so this changes nothing electorally, other than delivering a calculated insult to UUP voters and to the East Belfast electorate as a whole, by admitting the party is struggling.
“The people I represent deserve not to have their vote to taken for granted, but rather earned through engagement, commitment to work and a track record. The DUP-UUP clearly do not trust the people of East Belfast to exercise real choice.
“My vision is a more constructive form of unity - building a united community for all people of East Belfast, not a carve-up. Rather than denying people a choice, I offer them a real one: back to sectarian headcounts and the politics of fear and division, or forward to inclusive and progressive politics and a shared future.
“We have seen unionist pacts before – this did not work in Fermanagh-South Tyrone in 2010. It will be the same in East Belfast in 2015.”
Progressives can make gains despite unionist pact – Murphy
Sinn Féin MP Conor Murphy responded that the SDLP must now put progressive politics before its own narrow party political interests.
“The coming together of the two main unionist parties, the DUP and the UUP, in an election pact on a narrow sectarian and conservative agenda is a challenge to progressive politics,” he said.
“These parties have no vision for the future and are happy with crumbs from the Westminster table.
“This demands a strategic response from those of us who wish to see a society based on equality, inclusion and the protection of the most vulnerable.
“Nationalists, republicans and other progressives should come together to ensure maximum representation for parties committed to defending the core public services of health, education and the welfare state; parties which are unequivocally for equality and which are totally opposed to sectarianism, racism and homophobia.
“Martin McGuinness will be speaking to the SDLP leader Alasdair McDonnell at the earliest opportunity to explore an appropriate and strategic response to this pro-Tory alliance.
“We can only achieve this if the SDLP is prepared to put progressive, forward looking politics before their own narrow self-interests.”