Theresa May has defended the use of drone strikes against British citizens, saying the killing of Islamic State's Reyaad Khan in 2015 was "necessary and proportionate" and that she would authorise such strikes in the future. The prime minister said there had been no alternative to the killing of Khan in a precision airstrike in Syria because "a direct and imminent threat was identified by the intelligence agencies". There was "a clear legal basis for action in international law", she added. May was responding to the publication on Wednesday of a series of reports on counter-terrorism, cyber-security and other intelligence issues. The legality of drone strikes against a country's own citizens is controversial both in the UK and the US.