David Cameron rejects business leaders' criticism over 2017 EU referendum

PM rejects that he is playing politics and assures them he can win 'Yes' vote

David Cameron has reassured business leaders he can win a "Yes" vote to Britain remaining in the European Union and rejected their criticism that he is playing politics by calling a referendum.

Addressing the CBI's annual conference in London, the Prime Minister said his promise of a public vote by 2017 was not a "short term tactical ploy" but a "long-term strategic choice for Britain." Some businessmen have expressed concern that his populist move could end in Britain's accidental exit from the 28-strong bloc. The CBI will campaign for continued membership, which it says is worth between £62bn and £78bn a year to the UK economy.

But he admitted that public support for EU membership is now "wafer thin," conceding: "We haven't made the argument enough about why Europe matters and frankly there are lots of things in the EU that badly need reform: it is too costly; it is not flexible enough; it doesn't help our competitiveness enough. It needs to change."

Mr Cameron believed the case for a "Yes" would be strengthened once reform had been achieved. "I think that will be a much easier argument to win than the argument we would have if we had an in/out referendum today," he said. "I sit round that European Union table ... and I can see this organisation is going to change. It is changing in front of our eyes because of the euro. Those countries that are in the euro, they need change to happen. We shouldn't stand in their way. But I think it is perfectly legitimate to say 'You, the eurozone members need these changes. Well, we outside the euro, we need some changes too'."

Striking an optimistic note about winning a new settlement for the UK, Mr Cameron said: "It will be a much more balanced debate because we won't be arguing in/out on the status quo, we'll be arguing about staying in a reformed EU with a better deal for Britain. With the backing of organisations like this one and business voices about the importance of staying in a reformed EU, I think it is an argument we can win."

Ed Balls, the shadow Chancellor, told the CBI conference that leaving the Union would be "reckless, foolish and deeply damaging". He said: "Britain is better placed to shape Europe's future if we are fully engaged rather than having one foot out the door. We are clear that there is no future for Britain in walking away from our biggest market - or threatening to do so for reasons of internal party management."

Mr Balls added: "Europe needs reform, but to walk away from our EU membership would be reckless, foolish and deeply damaging. On Britain's future in Europe, the national interest must come first."

John Cridland, the CBI director-general, said Mr Cameron's speech was "an encouraging sign that we can work with Government to reform the EU from the inside. 'Inside with reform' is the only way to secure future growth and jobs."