DAVID Cameron has been urged by the leaders of Northern Ireland, Scotland, Wales not to hold his European Union referendum in June.
Arlene Foster, Nicola Sturgeon and Carwyn Jones warned that a vote in June would mean the referendum campaign clashing with the May elections to Stormont, Holyrood and the Senedd.
They first ministers said a June plebiscite "risks confusing issues at a moment when clarity is required" and called on Mr Cameron to "commit to deferring the EU referendum at least until later in the year".
The Prime Minister rejected the demand, committing to a gap of at least six weeks after the May 5 elections before holding the referendum - leaving open the possibility of a vote on June 23 or 30.
The letter, also signed by deputy first minister Martin McGuinness, said: "We believe that holding a referendum as early as June will mean that a significant part of the referendum campaign will necessarily run in parallel with those elections and risks confusing issues at a moment when clarity is required.
"Furthermore, it will be virtually impossible for the political parties in our respective territories to plan effectively for, and where appropriate work together on, the referendum campaign while our own elections are in progress.
"We believe that the European referendum is of vital importance to the future of the whole United Kingdom and the debate leading up to it should, therefore, be free of other campaigning distraction."
At Prime Minister's Questions, Mr Cameron insisted that voters would be "perfectly capable" of coping with two separate ballots.
He was urged to rule out a June referendum by the SNP's Westminster leader Angus Robertson.
Mr Cameron said: "There is no agreement, so no date has yet been fixed for the referendum."
He said former first minister Alex Salmond had called for a six week gap between the May contests and the referendum "and I can guarantee that won't happen".
The Prime Minister added: "I do respect the former first minister of Scotland who said six weeks was what was necessary.
"I also respect the electorates of England, Scotland, Wales and Northern Ireland on the basis that I think people are perfectly capable of making up their minds in a local election or in a Scottish parliamentary election, or in a Welsh assembly election and then, a period of some weeks afterwards, making up their mind all over again on the vital question of the European Union."
He told MPs: "This House has voted for a referendum. It would be pretty odd if, having voted for a referendum we then spend ages debating about not having one."
