David Cameron is facing questions over Britain's decision to follow the US model of drone strikes after the prime minister confirmed that the government had authorised an unprecedented aerial strike in Syria that killed two Britons fighting alongside Islamic State (Isis). Cameron justified the strikes on the grounds that Reyaad Khan, a 21-year-old from Cardiff, who had featured in a prominent Isis recruiting video last year, represented a clear and present danger". Two other Isis fighters were killed in the attack, [which was] the first time that a UK prime minister has authorised the targeting of a UK citizen by an unmanned aerial drone outside a formal conflict. One of them, Ruhul Amin, 26, was also British. A third Briton, Junaid Hussain, 21, was killed by a separate US airstrike three days later. Cameron disclosed the strikes in a dramatic afternoon statement which had originally been billed as a chance to outline his plans to take thousands of extra refugees from Syria. Downing Street dismissed suggestions that the prime minister had deliberately engineered UK involvement in the drone strikes rather than leaving them to the US ... as a way of making the case for greater British involvement in action against Isis in the country. Cameron, who had said that he would seek parliament's approval before extending any British military action against Isis targets from Iraq to Syria, said he had acted in line with his commitments, [because he] reserved the right to authorise strikes without a vote in the event of an emergency.