Conservative MP David Davis is building a cross-party parliamentary coalition to campaign for greater oversight of RAF drone strikes following the killing of two British citizens fighting with ISIS in Syria.
The longstanding civil liberties campaigner told BuzzFeed News that there is a major risk that such killings are "the first step down the American route" of drawing up "kill lists" of enemies the state wants to target.
"Whilst this undoubtedly decapitated al-Qaeda and other terrorist organisations it also killed a large number of innocent people," the former Conservative leadership candidate said. "And not only is that immoral and loses us the moral high ground completely, it's also completely counterproductive."
Davis said the initial gut reaction after seeing an ISIS fighter killed by drone was to shout "bloody hell, let's get another one".
"But that is a revenge reaction," he said. "It's always dangerous to make a judgement in the first flush after events. It's the point where those authoritarian tendencies are strongest – after 7/7 was when Blair tried to get 90 days through the House of Commons. That's when the jingoistic tendency is strongest."
Instead Davis believes he can form an alliance of MPs to impose checks and balances that would see a judge investigate every single targeted killing and consider the legality: "You can't introduce judges into the decision process – but you can say that every single named targeted killing needs to be reviewed after the event by certainty of evidence, risk to the public, assessment of any other way of dealing with it, and collateral damage."
Although this might not reduce the killings, he believes it would make ministers think twice before ordering a killing. "The point about all of this is it doesn't stop anything of itself," he added. "But it makes the minister and general look over their shoulder before they push the button if they know that someone's going to check the casework."
While he said it could take up to six months to gain support for such a proposal, he believes it will be possible to build a parliamentary alliance involving Labour, the SNP, the Lib Dems, and rebel Tory MPs that could force the government's hand.
"A significant number of SNP, Labour, and Liberals have been in touch about this," he said. "[Former attorney general] Dominic Grieve has also been questioning this.
"This is so new that people's opinions have not yet fully formed yet. When we had the Tory rebellion on Syria two years ago – which Cameron still largely blames me for, I'm told – the real leading light were ex-army officers: Crispin Hunt, Julian Lewis."
However, he admitted it would be hard to push through the plan without government support and said he would rely on making the moral case, since he would struggle to change the law: "The government will resist this, it will hate the idea."