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. The UK defence secretary, Gavin Williamson, in an interview with the Daily Mail in November, said Britons who have fought for Islamic State abroad should be hunted down and killed to ensure they never returned to the UK.

May’s response was more measured, saying the decision to kill a British citizen in an airstrike is one of the most difficult a government can face and should be taken only as a last resort.



Such is the sensitivity of the issue, Downing Street last year refused to provide key documents to the parliamentary intelligence and security committee, which had been investigating Khan’s killing. Its report was delayed until April and the prime minister was only now giving her response to that report.

Separately on Wednesday, the committee, chaired by the Conservative Dominic Grieve, also issued its annual report, which said an estimated 850 UK-based individuals travelled to Syria and Iraq to fight for Islamic State. Of these, half had returned to the UK and about 100 had been killed.

The committee’s report said: “Nevertheless, it is estimated that more than 300 UK individuals of national security concern remain in the region: when they decide to leave, the UK remains their most natural point of return.”



The committee said returnees presented a significant threat to the UK and urged the government to “ensure every returnee is fully assessed, that resources are made available such that appropriate monitoring continues on an ongoing basis and every effort is made to reintegrate children”.



Khan, 21, who was killed in an RAF drone strike in 2015, boasted on social media of murderous jihad. The strike was ordered by then prime minister David Cameron.



The committee also expressed concern about the increased pressure on the intelligence agencies in monitoring the large number of people imprisoned on terrorist offences who are due for release in the next two years.

Much of the intelligence committee report is devoted to the menace posed by cyber-attacks on the UK but also that the UK is expanding its ability to retaliate with cyber-attacks of its own.



The report says the surveillance agency GCHQ is expending more effort in developing hacking tools, ranging from “tactical stuff” to “the high end of counter-state offensive cyber capabilities”.

GCHQ is believed to have taken retaliatory action against North Korea, which was blamed for the WannaCry cyber attack that disrupted the NHS in May.

The committee said: “We recognise the importance of offensive cyber capabilities for the national security of the UK, although it will be important in the future to seek international consensus on the rules of engagement and we would support government attempts to establish this.”

It also warned the UK’s political system was a potential threat for cyber-attacks by hostile foreign states and terrorist groups – an issue raised during the June general election.

It expressed fear of the potential hacking of parliamentary or private computer networks. “It could also potentially include planting fake information on legitimate political and current affairs websites, or otherwise interfering with the online presence of political parties and institutions.”

The aim could be to subvert an election or referendum or poison public discourse, the committee said, urging political parties and parliamentarians to accept the offer of GCHQ to help improve their cyber-security.