With French and German elections to be held in 2017, Cameron has been urged to hold the EU referendum next year to avoid having his two of his key allies caught up on a domestic agenda.
However, given the EU's preoccupation with the Greek debt and refugee crises in recent times, not a great deal of attention has been paid to Britain's demands, with reports the PM is thinking of delaying the vote until the end of 2017 to buy himself more time to persuade other EU states to agree to his proposed reforms.
UKIP will work with anyone who wants to help get UK out of the EU. UKIP can't win #EURef on our own but it can't be won without us either
— UKIP (@UKIP) October 1, 2015
These suggestions have been shot down by Simon Walker, head of the business lobby group, the Institute of Directors (IoD), who told a business leaders function that delaying the vote would increase the risk of an "accidental Brexit", as it would coincide with a traditional dip in governmental popularity.
"The third year of an election cycle is a difficult time for any administration… If, after deliberation, the public votes to leave Europe, our members will have to accept it, and the period of uncertainty for business that will follow. They will be less philosophical if carelessness and domestic discontent led to an 'accidental Brexit'."
Brexit: '50-50 Possibility'
While in the past polls have suggested that a comfortable majority of Britons would prefer to stay in the EU, recent events have indicated that Euroscepticism may be on the rise as a result of Brussels' handling of the Greek debt and refugee crises.
"Britain voting to leave the European Union is at least a 50-50 possibility," Mr Walker said.
"My concern is the timing of the referendum. I hope this government will not drag out the referendum process any longer than necessary."
Walker warned that further delays in the referendum would create more uncertainty for businesses in Britain, which could halt investment and growth.
New #EUref poll shows "Remain" with 19 point lead over "Leave" Latest poll for Daily Mail http://t.co/YRqcxx6ur7 pic.twitter.com/hAXaYBrfe9
— ComRes (@ComResPolls) October 6, 2015
"While our members believe some uncertainty is a price worth paying to resolve EU membership, delay puts a brake on decision-making, investment and the vigor of their businesses," he said.
"A referendum in two years' time will see British concerns caught up in the crossfire of the French elections, in May [2017], and the German elections, in September."
The pressure is building on David Cameron to lock in a date for the Brexit referendum, while pro-EU Conservative MP Ben Howlett said Cameron needed to be clear about his specific demands, arguing that MPs were being left in the dark and did not "exactly know what the Prime Minister is renegotiating."
While external events in Greece and the Middle East are pushing the government towards delaying the referendum, business officials are leading the call for the vote to be brought forward, highlighting just how delicate and difficult the situation is for David Cameron.
