When the new TV debate proposals were revealed, I noted that while the SNP and Plaid Cymru had been added by the broadcasters (along with the Greens), the DUP, which has more seats than either (eight), had not. Unsurprisingly, the Northern Irish party has been quick to protest at the decision. Its Westminster figurehead Nigel Dodds has said it would be "ludicrous" to exclude them and its leader, Peter Robinson, has announced that he will be writing to the BBC and ITV "to identify why the DUP is not included in new debate format". He notes that they have "more seats than Plaid, SNP & Greens".

The question now is whether the Tories will support their cause, as they did in the case of the Greens (with David Cameron refusing to participate unless they were included). Cameron previously opposed the inclusion of non-English parties on the grounds that they are not fielding UK-wide candidates, but may amend his stance given how events have changed.

The Conservatives have long been courting the DUP in anticipation of the decisive role they could play in a hung parliament. But given the fragile state of politics in Northern Ireland, the broadcasters may feel uncomfortable about adding the unionist party without also having nationalist representation (in the form of the SDLP or Sinn Féin). This new dispute could yet provide Cameron with the excuse he wants to avoid the debates altogether.

Incidentally, if a seven-way debate seems unwieldy, here's Sweden's eight-way and Iceland's 11-way.