Parliament is expected to be recalled on Friday to discuss the UK’s role in air strikes against Islamic State, the BBC understands
There has been no official confirmation but an announcement could come later.
It is understood there has been a reluctance to make the announcement while Labour’s conference is under way.
It is also understood that there will be a formal request from the Iraqi Prime Minister later on Wednesday for the UK to join in air strikes.
David Cameron told NBC News in the US that the fight against Islamic State (IS) militants was one “you cannot opt out of”.
IS, also known as Isil and Isis, has taken control of large areas of Iraq and Syria in recent months.
“It has oil, it has money, it has territory, it has weapons and there’s no doubt in my mind it has already undertaken and is planning further plots in Europe and elsewhere,” Mr Cameron said.
The US and five countries from the Gulf and Middle East have begun bombing IS in Syria, BBC informs.