Yes, the drone strike on Reyaad Khan was legal

Was it right for an RAF drone to target and kill British “Islamic State” fighters? Post-Iraq and pre-Chilcot we tend to answer this question mainly in legal terms. The government says its lethal drone strike on Reyaad Khan and Ruhul Amin was lawful—and I think so too.

In international law, a country is allowed to use defensive force in accordance with article 51 of the UN Charter, which recognises the

"inherent right of individual or collective self-defence if an armed attack occurs ... "

Individual self-defence is, in our case, the protection of Britain itself; “collective” self-defence is when allies work together to defend one of them, as Britain’s doing currently with Iraq.

The wording of article 51 seems to suggest an attack must occur first before defence becomes legal. But it’s widely accepted a state can act first where necessary to ward off imminent attack.

The Prime Minister told us on Monday that Khan was indeed planning and directing armed attacks against the UK. But were Khan’s plans really “imminent”? I think so, unless he’d suddenly given up. The question of “imminence” is not about clock-watching. If he continued to plan and direct attacks then it’s likely they were impending, and due to happen before long.

It can’t be the law that Britain must know the precise date of planned attacks in order properly to stop them, or is obliged only to prevent them “downstream” in Britain itself. And the idea that Khan might be seen giving the fatal order or pressing some lethal button is surely fantasy: you can’t be required to wait for that. It was indeed necessary to strike at him, since no British boots on the ground are there to arrest him and Syria plainly can’t.

In the PM’s statement on Monday he cited only British self-defence — surprisingly, since Britain can lawfully fight Isis in Syria in collective defence of Iraq, which is threatened by Isis forces Syria cannot stop. The fact that MPs have not authorised action in Syria is irrelevant, in international law. And now it turns out from Britain’s report to the UN that the government does after all rely on both individual and collective defence to justify the strike. The PM perhaps foolishly thought it better not to raise the second argument in the House before MPs are asked to consider extending British operations to Syria.

Adding this argument does not, though, undermine the UK’s legal case. Some say the legal justification is “changing”, others that both arguments cannot be right. But they can both be right. Individual and collective self-defence are not mutually exclusive, and there is no contradiction between them. If Reyaad Khan was both planning and directing attacks against Britain and part of the general Isis armed force threatening Iraq, then targeting him was lawful in defence of both countries. The drone strike is doubly justified.

Of course it’s right to have as much disclosure as is safe and sensible about this operation, and that it’s properly scrutinised by MPs. If it turns out we’ve been lied to, and Reyaad Khan posed no threat either to Britain or Iraq, then I’ll have to change my mind. Otherwise, the strike was lawful.