Andy Burnham demands an in-out referendum is held next year

Andy Burnham demands an in-out referendum is held next year. Credit: PA

Labour leadership candidate Andy Burnham has upped the pressure on David Cameron over Europe by demanding an in-out referendum is held next year.

In a dramatic bid to outflank the Prime Minister, Mr Burnham declared he wants to change the Opposition's policy to support a national poll on the key issue.

He also warned Mr Cameron he would be "held to account" if he failed to negotiate a good settlement with Brussels that addressed concerns over immigration.

The intervention follows calls from Tory backbenchers for the referendum to be held earlier than 2017, as the premier has promised.

It comes as Labour figures brace for tension with the unions after Jim Murphy announced he was quitting as the party's leader in Scotland and delivered a stinging parting shot at Unite boss Len McCluskey.

Mr Murphy, who resigned despite winning a confidence vote, warned that Mr McCluskey was the "kiss of death" for Labour and condemned his "destructive behaviour".

Mr McCluskey is set to respond in interviews scheduled later.In an interview with the Observer, Mr Burnham said: "The country has voted now for a European referendum and under my leadership the Labour party will not be a grudging presence on that stage. We will now embrace it. It should be brought forward to 2016.

"It should be in the Queen's speech that it should be in 2016, and the message I would send to Cameron is that I would offer support to deliver it in 2016. It is not going to be in anybody's interest for this to rumble on through this parliament.

"We have to get to it. We have to do it, embrace the argument. That is the most fundamental problem facing British business right now."

Mr Burnham, who made clear he would campaign for an "in" vote, went on: "If Cameron doesn't deliver legislative change in terms of abuse of the rules of free movement by agencies and the effect on people with jobs here, it won't be good enough. It really won't be good enough.

"I am passionately pro-European. I cannot see how it could possibly be in the interest of this country to come out of the European Union. This is the challenge that prime minister has set himself and he has to deliver."