Cameron: EU referendum will not harm UK economy DAVID Cameron has tried to calm business by telling the Confederation of British Industry (CBI) conference that a referendum on EU membership will not harm the UK economy. But the Prime Minister has for the first time hinted at the prospect of recommending an exit vote, arguing that Britain cannot secure reform of the European Union by just saying it will "stick with whatever we have come what may." His message came as all three main party leaders addressed the CBI on the UK's future with Europe with Lib Dem Deputy Prime Minister Nick Clegg warning that leaving would be the equivalent of pulling up the drawbridge. Labour leader Ed Miliband said that departure from the EU represents "a clear and present danger" and an exit would "close the UK from the rest of the world." Mr Cameron's language on Europe noticeably hardened with the Tories facing a watershed by-election in the Rochester and Strood constituency where they face former Tory MP Mark Reckless who defected to Ukip over the UK's continued membership of the EU. But facing the pro-EU CBI he tried to play down the effects his proposed referendum in 2017 would have on the economy. "If there has been uncertainty, why is it that there has been such an extraordinary period of investment into our country?" he asked the conference. He went on: "The worst thing for us to do as a country is to pretend that this European debate is not happening. The best thing is to get out there and make the arguments. Mr Cameron defended his strategy of renegotiating the UK's EU membership before an in/out referendum in 2017, and told the CBI conference in London that by contrast Labour had no plans to reform Europe. 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 hit back by warning the same conference that "flirting" with withdrawal was a "betrayal of our national interest" and represented "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 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 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. Mr Cameron's strategy "has simply weakened our influence, not strengthened it," he said. Deputy Prime Minister Nick Clegg said it was "nonsensical" to threaten to leave the EU in an attempt to force through reforms. CBI Director-General John Cridland said: "The PM gave an upbeat speech with deficit reduction firmly in pole position. There was recognition that it is necessary to grow at the same time as cutting back, and it was good to hear the emphasis on both infrastructure investment and skills. "Business will welcome the PM's endorsement of the CBI's Europe strategy of "In with Reform."" EU referendum mirrors SNP's narrow nationalism