LONDON - Prime Minister David Cameron pledged to fight hard in 2016 to resolve annoying features of Britain's relationship with the EU ahead of a planned referendum that could come this year.

Cameron said aspects of being in the European Union were the cause of "so much frustration" in Britain - but ultimately voters would decide whether the country remains in the bloc. He is attempting to renegotiate the terms of Britain's membership, ahead of an in-or-out referendum which must happen by the end of 2017.

No date has been set for the vote, though newspapers and political commentators have speculated that it could well come in 2016.

"It's a New Year, and Britain begins it with renewed strength. With a lower deficit and enterprise flourishing, our economy is becoming more secure by the day," Cameron said. "I am negotiating hard to fix things that most annoy British people about our relationship with the EU," he said in his New Year message.

"It is a difficult negotiation with 27 other countries. But throughout we are driven by one consideration: what is best for Britain's economic and national security. "In the end, you will decide whether we are stronger and better off with our European neighbours as part of the European Union, or on our own."

Cameron said he thought Britain was in the middle of a "great reforming decade", a "turnaround" period where a revived economy could spur "real social renewal". "We remain on the long walk to a Greater Britain. We won't get there overnight. But during 2016, we will make some of our most significant strides yet," he said.

A poll in The Times newspaper found that 42 percent wanted to leave the EU, while 41 percent wanted to stay.

However, 55 percent said they expected Britain would vote to stay, while 27 percent expected Britain would vote to leave. Only nine percent expect Cameron's renegotiation efforts to produce significant change.

The YouGov poll was conducted on December 17 and 18. The Times said voters would have to decide whether Britain can "better help to reform a tired and ageing Europe from inside or out". "Britain needs Europe to succeed... the EU at its best could be formidable," it said in its editorial.

"The shock of one of its fastest-growing economies leaving might be the wake-up moment that precipitates the redesign of European institutions."

While official Remain and Leave campaigns will be designated, an independent think-tank on Friday urged a neutral campaign group to be established to boost turnout.

British Future, which focuses on migration and integration, said such a campaign should focus on trying to reach groups who are traditionally least likely to vote.

"The EU referendum will give Britons one of the most important choices in a generation. Yet many voters are undecided, unaware or simply not bothered," said BF's director Sunder Katwala. "Such a big decision needs a big referendum - one that engages as much of the country as possible. "It gives more legitimacy to the decision we make."