Northern Ireland's first minister has written to broadcasters in the UK, demanding to be included in their election debates.

Peter Robinson's intervention follows a row between the broadcasters and David Cameron about how the debates should be run.

The prime minister is refusing to take part unless the British Green Party is also included alongside UKIP.

Broadcasters have now agreed to include the Greens, as well as nationalist parties from Wales and Scotland.

But that has drawn criticism from the DUP, which says it's the fourth-biggest party in Westminster and which says it should also be allowed to take part.

Mr Robinson has written to the broadcasters, saying the decision “cannot logically or legally be defended.”

“What is not acceptable is a situation where the largest party in Northern Ireland is to be excluded while regional parties from Scotland and Wales, with fewer seats in Parliament than the DUP, are to be included,” Mr Robinson added.

“The proposed decision is rightly seen as a further attempt by the broadcasters to marginalise Northern Ireland from the national debate,” he said.