The UK government is among a group of countries that are attempting to thwart plans to formulate and impose a pre-emptive ban on killer robots.

Delegates have been meeting at the UN in Geneva all week to discuss potential restrictions under international law to so-called lethal autonomous weapons systems, which use artificial intelligence to help decide when and who to kill.

Most states taking part – and particularly those from the global south – support either a total ban or strict legal regulation governing their development and deployment, a position backed by the UN secretary general, António Guterres, who has described machines empowered to kill as “morally repugnant”.

But the UK is among a group of states – including Australia, Israel, Russia and the US – speaking forcefully against legal regulation. As discussions operate on a consensus basis, their objections are preventing any progress on regulation.

The talks come as the UK military is ploughing tens of millions of pounds into autonomous weapons, most recently announcing on Thursday a £2.5m project for “drone swarms” controlled with the help of next-generation autonomy, machine learning, and AI.

The talks in Geneva are taking place under the convention on certain conventional weapons. First enacted in 1983, the convention is intended to restrict the use of weapons “that are considered to cause unnecessary or unjustifiable suffering to combatants or to affect civilians indiscriminately”. It already covers landmines, booby traps, incendiary weapons, blinding laser weapons and clearance of explosive remnants of war.

“We urgently need a ban on killer robots,” said Ben Donaldson, head of campaigns at the United Nations Association – UK. “The majority of states get it. A rapidly growing proportion of the tech community get it. Civil society gets it. But a handful of countries including the UK are blocking progress at the UN. The UK needs to listen to this growing coalition and join calls for a preemptive ban.”

Responding to the criticism, a Ministry of Defence spokesperson said: “The United Kingdom does not possess fully autonomous weapon systems and has no intention of developing them. We believe a preemptive ban is premature as there is still no international agreement on the characteristics of lethal autonomous weapons systems.”

The issue of human control is at the heart of discussions about killer robots, according to the British military, and its negotiators have sought to focus debates at the UN on building consensus on what that means. Britain’s negotiating team says that no UK offensive weapons systems will be capable of attacking targets without human control and input.

They are arguing against a preemptive ban on the basis that it could jeopardise their ability to exploit any potential military advantages they could gain by imbuing weapons with AI.

“What’s being said is that current humanitarian law is enough,” said Taniel Yusef, international adviser for the Women’s International League for Peace and Freedom, who is in Geneva lobbying for a ban. “But robots can’t make ethical and legal decisions.”

Those backing legal controls say the UK’s position masks potential for the development and deployment of weapons with significant levels of autonomy. Military commanders already possess weapons that, once launched, can identify their own targets within a limited area, they point out, and the potential with AI is expanding such uses over a wider area for longer.

“It then becomes more difficult to assert that it’s the commander that has really made the decision or whether the attack was made without much human involvement at all,” said Richard Moyes, managing director of Article 36, a UK-based non-profit organisation that campaigns for more control over new weapons technologies.

“The UK should be under some pressure on this issue. There are officials in the UK who are quite thoughtful on this stuff and I feel that the posture the government takes in the talks is quite unhelpful. They are being a brake on movement towards agreement rather than positively pushing forward.”