London, Paris tighten nuclear bond over US, Russia concerns

London, Paris tighten nuclear bond over US, Russia concerns
By Mathieu RABECHAULT and Fabien ZAMORA
Paris (AFP) July 10, 2025

Britain and France took a key step to underpin Europe's security by agreeing to tighten nuclear cooperation, as the region frets over the US commitment to its defence and Russian ambitions.

In targeting a "reboot" of defence ties with a focus on joint missile development and nuclear co-operation, while also firming up support for Ukraine in its war with Russia, Europe's two nuclear powers also hope to send a strong signal to Moscow.

- What is the UK and France's nuclear stance? -

Right from its inception, France's nuclear deterrent was designed to be independent, its potential deployment subject to the French president's evaluation of any perceived threat to the republic's strategic interests.

According to the independent Stockholm-based Sipri Institute on global security, France has 290 nuclear warheads, some carried aboard four submarines and some by Rafale fighter jets.

Britain for its part has 225 nuclear warheads. For now, the British nuclear deterrent is purely sea-based, carried by four submarines armed with ballistic missiles.

However, the British government announced last month it would add an airborne component to its operational system with the purchase of 12 American F-35 fighter jets.

Unlike France's, Britain's nuclear forces are fully integrated under the NATO defence umbrella to cover the Western military alliance's 32 member states.

On Thursday during a visit by its President Emmanuel Macron to London, France agreed to the principle of coordination with Britain despite nominal national independence.

Despite the cherished independence of the French deterrent, Macron remarked in 2020 that France's vital interests have an "authentically European dimension".

In a 1995 joint declaration Paris and London acknowledged that "the vital interests of one (partner) could not be threatened without the vital interests of the other equally being at risk".

- What's new? -

Whereas that declaration was limited to the definition of the two neighbours' "vital interests", the latest cooperation accord goes much further.

The 1995 accord "was a uniquely Franco-British declaration on a very political level", said Heloise Fayet, a researcher on nuclear issues at the French Institute for International Relations.

In the latest announcement, "the reference to nuclear arms is much more visible and clear," Fayet told AFP.

"There are two advances: on the operational level with this coordination of the two deterrents. And the second is obviously the expansion of the joint European dimension."

Thursday's declaration stated that the respective deterrents of London and Paris remain under national control "but can be coordinated".

It added "that there is no extreme threat to Europe that would not prompt a response by both nations", the UK defence ministry and the French presidency said in a statement.

London and Paris also said they would further underpin cooperation by creating a nuclear supervision group which, says Fayet, "deepens the existing consultation mechanism".

- Complications for Russia? -

For Artur Kacprzyk of Poland's PISM research institute, the declaration was "still ambiguous" regarding the possible response to an "extreme threat".

"It obviously doesn't mean automatic use of nuclear," Kacprzyk told AFP, but sends an "additional signal to the Russians that there could be a joint French and British nuclear response to an attack on allies... It complicates the calculus for Russia."

Fayet said London and Paris were sending a message that they can deal with "an extreme threat to Europe via conventional responses, cyber attacks -- and nuclear, evidently".

She judged it "truly an additional step with an unprecedented level of military and political coordination", opening up the possibility notably of joint submarine patrols.

That, for instance, could see an attack submarine from one cross-Channel partner escort a ballistic missile submarine from the other or participation of British aircraft in French exercises.

- What's in it for the rest of Europe? -

"It's a welcome development for European security and deterrence of Russia, although not a revolutionary one, at least not yet as we don't know the details," said Kacprzyk.

"It sends a strengthened message of deterrence to Russia" even if in practice this "depends a lot on implementation", he added.

The move comes at a time when "a lot of Europeans are getting concerned about the US" and its commitment to Europe's defence, said Ed Arnold, an expert at Britain's Royal United Services Institute.

For Fayet, "other European countries can only welcome Franco-British cooperation, as long as it translates concretely and swiftly in operational terms into Franco-British discussion mechanisms with other countries."

Kacprzyk added: "There are many, many steps that both can take together or separately to further strengthen European nuclear deterrence, like having more nuclear forces or, as Macron mentioned, deploying some of them on allied territories."