Ed Miliband, Nick Clegg and Nigel Farage are today piling the pressure on David Cameron to agree to appear in leaders’ debates before the election. The Labour, Lib Dem and UKIP leaders have each sent the PM a letter with identical wording, warning him that to avoid the debates due to “political self-interest” would be “unacceptable”.

The letter refers to a joint proposal made by the BBC, ITV, Channel 4 and Sky in October, suggesting a set of three debates featuring the four party leaders. If Cameron does not reconsider his position, the other leaders threaten to attempt to carry out the debates anyway.

Cameron last week said that he would not join the debates unless an invitation was also offered to the Green Party leader Natalie Bennett – yet he has been dragging his feet over negotiations since before the broadcasters’ proposal was even made.

That Miliband has been willing to co-ordinate this letter with Nigel Farage is interesting: only last year he suggested he was not in favour of the UKIP leader joining the debates. At the time, he said: “I look forward to debating David Cameron. I am not that interested in Nigel Farage. I care about debating David Cameron.”

You can read the full text of today’s letter here:

Dear David

In 2010 the televised leaders’ debates provided an unprecedented opportunity for voters to see the party leaders debate the critical issues facing our country. The debates were watched by more than 20 million people and enthusiastically endorsed by all those who took part, including yourself.

In recent days, you have announced that you are unwilling to take part in debates as proposed by the main broadcasters for the 2015 General Election. I believe it would be a major setback to our democratic processes if these debates were not repeated in 2015 because of one politician’s unwillingness to participate.

I hope you will agree that the decision as to who should take part in the televised debates should not be in the hands of any party leader, each of whom inevitably has their own political interests to defend. It must be a decision independently and objectively arrived at.

As you know, the broadcasters, who have strict obligations of political impartiality under the BBC Charter or their Ofcom licences, have together made such an objective determination. While each of the other parties invited to take part in the debates has their own views on the proposal and the levels of participation offered and will continue to make their case in this regard, we all accept the independence and impartiality of the broadcasters and have committed to take part in the debates.

It would be unacceptable if the political self-interest of one party leader were to deny the public the opportunity to see their leaders debate in public. Therefore, if you are unwilling to reconsider, the three party leaders who have committed to participate will ask the broadcasters to press ahead with the debates and provide an empty podium should you have a last minute change of heart.

These debates are not the property of the politicians and I do not believe the public will accept lightly the prospect of any politician seeking to block them.

Yours sincerely​

Ed Miliband MP