This seat in Northern Ireland could help decide the General Election

With a day to go to the General Election, no party is looking on track to secure a comfortable victory. One frequently ignored implication of this is that Northern Irish parties could play the most important role this time than in any election since the 1970s.

Here's why: If the Conservatives do become the largest single party with around 280-290 seats, as most forecasters expect, it will still leave them needing to find coalition partners with which to form a government.

Given recent history, the party is almost certain to approach the Liberal Democrats first, especially since Nick Clegg has already stated his intention to allow the largest party by seats the right to attempt to for a government first. However, unlike in 2010, the Lib Dems will struggle to return the seats that would be required in order to re-form the current coalition government by themselves.

So what then?

Well, the Tories aren't really spoilt for choice. The Scottish National Party (SNP), which the polls suggest is on track to pick up as many as 50 seats on May 7, has ruled out any kind of deal that would allow a Conservative government into office while a Grand Coalition involving Labour remains well outside of the realms of possibility.

Of the others, Welsh nationalists Plaid Cymru might take as many as five seats and the Greens could hold onto their current seat in Brighton Pavilion, but both are every bit as unlikely as the SNP to want to work with the Conservatives.

Instead the Conservatives are likely to have to look to the Northern Irish Democratic Unionist Party (DUP) or the UK Independence party. The clear preference expressed by the Tory leadership is to avoid having to do any sort of deal with Nigel Farage - so the Northern Irish party is likely to hold a lot of cards.

And here's how the polling looks for them - at present the party is on track to win nine seats:

Of them, the one to watch is likely to be Upper Bann. As polling company Lucid Talk writes of their findings (emphasis added):

As can be seen the biggest change since our March poll has been in Upper Bann which has dropped from an 80% score for the DUP to 65%. This seems to be mostly due to the strong challenge that the UUP's Joanne Dobson has been mounting against the sitting MP the DUP's David Simpson. However, what should worry the unionists is that our models now show there is not just one alternative to the DUP, but two i.e. Sinn Fein and the UUP. Some comments from our Opinion Panel members in Upper Bann say that Catherine Seeley the Sinn Fein candidate could 'come through the middle' if the DUP and UUP evenly split the Unionist vote.

Let's go back to the seat forecasts to see what impact the result suggested by the poll could have on the result. If Sinn Féin does take the seat from the DUP the net result is that the Conservatives lose a seat that they could otherwise have brought into a government. (NB Sinn Féin does not take up its seats in Westminster so they will not be part of any coalition negotiations)

Another potential uncertainty according to the poll is Belfast South which could go in the DUP's favour, though that is significantly less likely.

In a race this tight, where one seat could make the difference between hitting that magic 323 figure and being unable to form a stable government, these seats are likely to matter. It's time we started paying a bit more attention to Northern Ireland - and to Upper Bann in particular.