British pilots have taken part in US and Canadian air strikes against Islamic State group targets in Syria, the defense ministry said on Friday, despite a vote in parliament in 2013 against military action.
"The UK is not conducting air strikes in Syria. But we have a long-standing embed program with allies, where small numbers of UK personnel act under the command of host nations," the ministry said.
"That has been the case in Syria, although there are currently no pilots operating in this region," it said, adding that the number of pilots involved was fewer than 10.
In 2013, Prime Minister David Cameron's government suffered a setback when it lost a vote on Syria air strikes because of opposition from the Labour party.
Lawmakers last year voted in favor of air strikes against ISIS jihadists in Iraq, but not in Syria.
Eight British RAF Tornados based in Cyprus are carrying out air strikes over Iraq as part of US-led operations and Britain currently also has three spy planes flying missions in the region.
Days after 30 Britons were among 38 tourists killed by a jihadist on a beach in the Tunisian resort of Sousse last month, Defense Secretary Michael Fallon hinted that Britain's parliament could be asked to vote again on joining air strikes on targets in Syria.
He told the BBC that ISIS "has to be defeated in both Syria and Iraq" and that there was "an illogicality" about not being able to strike targets in Syria.
Cameron favors exploring a second vote to gain support for air strikes in Syria later this year after Labour has elected a new leader in September who could give him the support he would need to get the move through parliament.