UK will not rule out more drone strikes – Fallon

Mr Fallon said an RAF strike in Syria, which killed two British Islamic State jihadists, was “perfectly legal” and he “would not hesitate to do it again”.

He admitted to being the one who authorised the drone strike and claims he had no other option but to defend Britain from a terror threat.

“This action was absolutely legal providing it was necessary and proportionate,” Mr Fallon told ITV’s Good Morning Britain.

“There was no other way of dealing with these particular terrorists, they weren’t going to come back to this country to be prosecuted or stand trial. There was no other way of preventing the kind of armed attack they were involved in planning. Any country has the right to defend itself from an armed attack and that’s what we did,” he added.

David Cameron told MPs on Monday that two British citizens were killed in August in a targeted drone strike on the Isis stronghold of Raqqa, Syria.

Cardiff-born Reyaad Khan and Ruhul Amin, who were identified as Isis fighters, were killed in the drone strike, marking the first time Britain has used such an attack in a country it is not at war with. A third unidentified man was also killed.

The prime minister said the attack was legal and revealed Khan was accused by the intelligence services of plotting “barbaric” attacks on “high-profile public commemorations” in the UK.

He said: “I can inform the house that in an act of self-defence and after meticulous planning Reyaad Khan was killed in a precision air strike carried out on 21st August by an RAF remotely piloted aircraft while he was travelling in a vehicle in the area of Raqqa in Syria.”

The drone strike has come under criticism and Mr Cameron has been warned that he could face a legal challenge to the targeting killings.

Former attorney general Dominic Grieve said that while the decision to kill the men in an act of “self-defence” could be legally justified, the strike could also be could be looked at by the independent terrorism reviewer or challenged in the courts on human rights grounds.

MPs also raised concerns that the strike could set a “dangerous precedent” and Michael Clarke, director general of the Royal United Services Institute, said the government appeared to have “decided to create a momentum to action that might be unstoppable”.