DAVID Cameron has upped the ante in the battle for the business vote by telling Britain's captains of industry that Ed Miliband regarded them as "the enemy" and, if Labour got into power, it would demonise them for creating wealth.

But Ed Balls, the Shadow Chancellor, hit back, reinforcing the fears of some business chiefs that the Tory plan to hold an in-out referendum on the UK's membership of the European Union was the "biggest risk to our economy in the next decade."

Both politicians spoke at the annual conference of the British Chambers of Commerce in London, where the body's Director General John Longworth warned that prolonged uncertainty over Britain's membership of the EU would result in what happened before the Scottish independence referendum with firms withholding investment pending the outcome of the poll.

"Britain will be in the same position as Scotland was," he told his business colleagues, stressing that any referendum should be fast-tracked and take place "in the first year of the next parliament" ie 2016.

Following several days when Labour's relationship with business has come under critical scrutiny, the Prime Minister used his speech to the BCC to emphasise his campaigning message that Labour would be bad for business.

After urging firms to spread the benefits of economic recovery by giving their workers a pay rise, he said that the long-held political consensus, as seen under New Labour with Tony Blair and Gordon Brown, that business was the generator of growth, was over.

The Tory leader mimicked a famous speech by ex-Labour leader Neil Kinnock to drive home his point, saying: "I warn you not to grow your business because they'll come after you. I warn you not to take people on because they'll slap taxes on you. I warn you not to create wealth because they'll demonise you. I warn you not to aspire to aspire, to work, to turn a profit, to build something better because, in their vision, you are the enemy; private sector 'bad', public sector 'good'."

But Mr Balls, saying he agreed with Mr Longworth that Britain had to lead the debate on reforming Europe so that it worked better for this country, warned that the UK should not flirt with exit.

"While I agree with John about the need for reform and about the damage the current uncertainty is doing for investment, I fear every comment by senior Cabinet ministers saying they would be happy or relaxed for us to walk out of Europe and every hint that a referendum could happen as early as next year, before any meaningful reform could be achieved, only adds to the uncertainty and the risk for British business.

"I fear Britain walking out of the EU is the biggest risk to our economy in the next decade," declared the Shadow Chancellor.

His colleague Chuka Umunna, the Shadow Business Secretary, after a week of Tory claims of Labour's anti-business mindset, ramped up his party's pro-business rhetoric, telling the conference: "We will work every day, strain every sinew, to make your lives that bit easier; easier to do business, easier to export, easier to create jobs, easier to succeed."

But Lord Mandelson, the former Labour Business Secretary, suggested Mr Miliband risked alienating the country's entrepreneurs with his "body language" on business.

"You must never use language or even body language, let alone what you say, that creates the impression that you are for or against any section of society, of the economy," explained the Labour peer.

He stressed how the party leader was bringing forward policies that supported business and urged him to "plough on through this campaign being true to himself, setting out clearly what he believes in".

Meantime, Mr Cameron announced that a future Tory government would plug a £1bn annual funding gap for business in a bid to emulate the German model of successful "Mittelstand" or medium-sized companies.

The Help to Grow scheme would involve helping 500 fast-growing firms a year, using either the UK Government's balance sheet strength to guarantee loans or investing public money alongside private funding.