BRITAIN cannot secure reform of the European Union by just saying it will "stick with whatever we have come what may", David Cameron has said.

Giving his strongest signal yet that he could support an exit without significant concessions, Mr Cameron defended his strategy of renegotiating the UK's EU membership ahead of an in/out referendum in 2017 and told the CBI conference in London that Labour by contrast had no plans to reform Britain's relationship with Europe.

Opposition leader Ed Miliband hit back by warning the same conference that "flirting" with withdrawal was a "clear and present danger to our future prosperity".

Mr Miliband pledged that, as Prime Minister, he would "never risk British businesses, British jobs, British prosperity by playing political games with our membership of the European Union". Mr Cameron told the CBI: "Britain's future in Europe matters to our country and it isn't working properly at the moment and that is why we need to make changes. I agree with what the CBI has said: we should be looking for a reformed European Union.

"Now I am the politician who has the plan for that reform, who wants to see the single market safeguarded and not have us ordered around by the single currency countries, who wants to make sure we belong to a Europe that is about a common market and co-operation and not about ever-closer union.

"And I want to be part of a Europe that addresses people's concerns including immigration." He added: "I am clear: these things can be done. These things can be negotiated and we can then hold that referendum and give people a proper choice about staying in a reformed European Union or opting not to belong to it."

In a clear dig at Mr Miliband, he went on: "That is a plan. That is a strategy to secure the best future for Britain. Simply standing here and just saying 'I will stay in Europe, I will stick with whatever we have come what may' that is not a strategy, that is not a plan and that will not work."

Mr Miliband used his own address to warn: "There are some people in our country who advocate exit from the EU. There are others who flirt with it, thinking they can do so without consequence and perhaps with advantage to Britain.

"In my view both are equally dangerous. It is a betrayal of our national interest. It is a clear and present danger ... to businesses that trade with Europe every single day."

In a clear reference to Mr Cameron, Mr Miliband added: "Giving succour to the argument that the real answer is leaving the EU, or contemplating it, simply drags us closer to exit.

"And every nod and wink to those who want to leave sends a message to potential investors in our country that we are not open for business, that our country is a dangerous bet."