France didn’t tell Britain about secret ‘kill switch’ in Falklands Exocets, admits official

France refused to tell Britain how to stop Exocet missiles during the Falklands war because it did not want to hand "the keys to the safe" to a rival in the arms trade, a former French defence official has admitted.

Pierre Razoux said the French had a defeat device that could "kill" an incoming missile, but Francois Mitterrand, the then president, would not share it with Britain.

Exocets fired by Argentina during the conflict claimed 46 British lives when they sank two ships and severely damaged a third.

It came as the new First Sea Lord revealed he had raised the matter with his French counterpart after The Telegraph reported claims that France had withheld information about a "kill switch" in the missiles.

Admiral Sir Ben Key said he had been assured that no such device existed, but stressed that the Royal Navy would support an inquiry into the matter if the Government decided to hold one.

Senior MPs responded by stepping up demands for the French government to come clean, with one saying it was important to find out whether France could have done more "to save British lives".

This week marks the 40th anniversary of the Exocet strike that sank HMS Sheffield, and Mr Razoux, a civil servant in the French ministry of defence from 1992 until 2020, disclosed that French naval vessels were equipped with electronic countermeasures that could "neutralise" French-made missiles if they were ever used against them.

He said France had handed over "part of the technical details" of the Exocets along with a large amount of intelligence about Argentina's weapons stockpile, but stopped short of providing Britain with the box-like device that could stop an Exocet in its tracks.

Mr Razoux said: "To my knowledge, this kill process… was only activated when the missile received a message from the target itself. Just like boats from the Royal Navy, French ships in a war zone had a series of electronic countermeasures that emit signals to neutralise missiles that we could have sold and could be used against us.

"It is an object – a type of box – that emits a signal on a particular frequency with particular data. It's as if you had a whistle or a flute. Each one has a different sound and frequency. Without the right emitter you cannot neutralise, but to hand this over is like giving the keys to your safe to your neighbour. It's not done."

Without the vital device, Britain's only defence against the radar-guided missiles was trying to lure them away from their targets, using clouds of metal strips fired from the ships and decoys trailed from helicopters. Some of the tactics were developed after Ministry of Defence scientists resorted to dismantling an early version of an Exocet to see how it worked.

Mr Razoux, who has written a book about the Falklands war and now works for a research institute funded by the French ministry of armed forces, also worked for the UK Minsitry of Defence as a liaison officer from 2000 to 2003.

Asked why the Mitterrand government had stopped short of giving Britain the ability to "kill" Exocets, he said: "It is because we were and still are competitors in the arms industry and Francois Mitterrand knew that if he had handed over the plans in full then the British would have let it be known the world over.

"That would have been very bad publicity for the French arms industry at a time when the French and British industries were competing fiercely in a certain number of key markets."

Bob Seely, a Tory MP and a member of the Commons foreign affairs committee, said: "It now seems clear that the French could have done more to help, and that is pretty disappointing if true because we would undoubtedly have saved British lives. All the more reason why the French should now be transparent about what happened."