LONDON - British Prime Minister David Cameron will allow his government ministers to campaign for or against Britain remaining in the European Union ahead of an in-out referendum, the BBC reported Tuesday.

Cameron has vowed to campaign in favour of staying in the bloc if he secures reforms to Britain's relationship with the EU before the vote. But some eurosceptics on the right of his Conservative Party - including some ministers - are set to defy him and back a "Brexit".

In order to avoid a damaging clash and forced sackings, Cameron is to allow ministers to campaign for either side once a deal is reached on Britain's membership terms, the BBC reported.

He is expected to confirm the news in an official statement to members of parliament at around 1530 GMT.

Cameron's official spokeswoman did not deny the report but called it "speculation" at a regular briefing with journalists.

The referendum must be held by the end of 2017, but Cameron has not yet set a date. Analysts suggest that the middle of this year is the most likely date.

The prime minister hinted last month that he would hold the referendum in 2016 after securing a deal on his "Brexit" reform demands.

Cameron said after an EU summit in Brussels that his government aimed to achieve a breakthrough at the next summit in February and then encourage British voters to support continued membership.

"I believe that 2016 will be the year we achieve something really vital, fundamentally changing the UK's relationship with the EU and finally addressing the concerns of the British people about our membership," he said. "Then it will be for the British people to decide whether we will remain or leave."