The DUP have hinted that they could launch legal action over their exclusion from upcoming televised debates ahead of the general election.
The party has written a letter to the broadcasters concerned in which it complained about moves to include Plaid Cymru, The Green Party, SNP and UKIP – but not the DUP, which holds more seats than any of them.
Although the party did not explicitly say it will fight the decision through the courts, it stated that “the broadcasters’ decision cannot logically or legally be defended” – and pledged the party to pursue “all suitable remedies” to get it changed.
It also sent the letter to broadcast regulator OFCOM.
Back in October, broadcasters had announced that UKIP would participate in a TV debate with the three main Westminster parties – but not the Greens.
And earlier this month David Cameron said he did not wish to take part in such an arrangement if the Greens were not also involved.
The four major broadcasters have now confirmed plans for a 7-7-2 format for TV debates.
Under this arrangement, two debates hosted by the BBC and ITV will feature the leaders of Conservatives, Labour, Liberal Democrats, Ukip, the Greens, Scottish National Party and Plaid Cymru.
A third on Channel 4 and Sky would pit David Cameron against Ed Miliband in a head-to-head clash.
Peter Robinson said in his letter: “MPs elected in Northern Ireland are of equal status to MPs elected in any other part of the United Kingdom. After this election, there is a real possibility that Northern Ireland MPs could have a crucial role in the formation of the next UK government...
“The proposed decision is rightly seen as a further attempt by the broadcasters to marginalise Northern Ireland from the national debate.”
It demands an explanation for the decision, and calls on all concerned to “revisit your proposal to exclude the DUP as a matter of urgency”.
In addition to the furore around the debates, OFCOM launched a public consultation this month on which parties should be considered “major parties” for broadcast purposes.
The proposal recommends extending this designation to UKIP, but not to the Green party or TUV (it already recognises the SDLP, UUP, DUP, Sinn Fein and Alliance as “major” parties in Northern Ireland).
The consultation ends on February 5.
However, OFCOM said that this largely only affects the number of party political broadcasts which each party can receive, and does not influence the televised debates.
It said that this is “an editorial matter for broadcasters”.