David Cameron finds changed political landscape in Northern Ireland

David Cameron and his wife Samantha were shown props and backdrops from the Game of Thrones TV series during their visit to Belfast

David Cameron's Game of Thrones visit to Belfast ticked a "four nations" box for the Conservatives.

But it also emphasised how much has changed in the last five years.

In 2010, the Conservatives and the Ulster Unionists were partners in an electoral pact, and Mr Cameron harboured hopes Northern Ireland's "New Force" might contribute an MP to his Westminster team.

Now older and wiser, Mr Cameron knows his Northern Ireland candidates are embarked on a long process of trying to build from the bottom up.

In the 2015 electoral Game of Thrones, the New Force has been replaced by a DUP-UUP pact, and the real Northern Ireland dynasty in play is the DUP, hoping to increase its complement of MPs and return as kingmakers in a hung parliament.

Voter motivation

If the arithmetic doesn't work out on 8 May, no doubt the DUP will be disappointed.

But so far as the current campaign is concerned that doesn't matter - the party is using the prospect of wielding influence as an impetus to motivate its vote right now.

DUP strategists appear confident of retaking the East Belfast seat lost five years ago to Alliance.

While Naomi Long may benefit from incumbency, the odds look stacked against her.

The DUP is also hopeful about profiting from any damage to the SDLP's South Belfast vote caused by Sinn Féin entering the race there.

Aside from calling for an end to the bedroom tax and a guaranteed level of defence spending, one aspect of the DUP's Northern Ireland plan which Peter Robinson referred to in his recent Inside Politics interview, is its rejection of the previous proposal to cut Northern Ireland's constituencies down from 18 to 16 (as part of a general reduction in the size of the Commons).

Previously the Conservative-backed plan foundered when the Liberal Democrats pulled the plug.

But if David Cameron does return to power with DUP assistance he will find them equally opposed, at least so far as Northern Ireland is concerned.

If the DUP can consolidate or improve its Westminster position in this election, it doesn't want to allow it to be subsequently reduced by a stroke of a Boundary Commissioner's pen.