The first thing to note is that Sinn Fein remains committed to its policy of not taking its seats at Westminster. So every Sinn Fein MP elected reduces the number that a party needs to have an effective majority in the Commons.
Iris Robinson, expenses and the rise of Traditional Unionist Voice have all rather dented the DUP, the largest party in Northern Ireland at the last election. But it should still send back a fair few MPs. The DUP’s modus operandi during the vote on 42 days suggests that in a hung parliament they will try and extract as many perks for their constituencies as they possibly can.
Any MPs elected by the alliance between the Tories and the Ulster Unionists will take the Tory whip. The expectation is that this should produce two to three MPs taking the Tory whip. (SDLP MPs take the Labour whip, showing just how hypocritical Shaun Woodward’s attack on the Tory UU partnership was.) Sylvia Hermon, an independent Unionist who refused to join the Tory UU alliance, is expected to be re-elected and she will take anyone but Cameron's approach.
For the first time, Northern Ireland is counting overnight, so we’ll know what effect Ulster has had on the result by Friday morning. If the Tories do pick up two to three seats, they could well have more MPs in Ulster than Scotland.