RAF Typhoons have escorted French Rafales simulating a nuclear strike mission over the Mediterranean, the first time British aircraft have taken part in a French nuclear exercise, according to the government.

Exercise Rummy ran on 20 and 21 October, with the Rafales launching from Saint-Dizier air base in eastern France, the home of the French air force’s airborne nuclear component. No nuclear weapons were involved, and the Ministry of Defence said the exercise was conducted under robust safety and security arrangements and focused on how the two air forces work together.

Wes Streeting, the Defence Secretary, said: “This exercise marks a new chapter in the defence nuclear relationship between the United Kingdom and France.

“As Europe’s nuclear powers, we have a shared responsibility to contribute to the security and stability of the Euro-Atlantic region. This exercise demonstrates the depth of our partnership, the credibility of our deterrents and our determination to stand together in the face of emerging threats.

“In an increasingly dangerous world, our adversaries should be in no doubt: the UK and France remain united in our commitment to European security and to maintaining the deterrence that has helped preserve peace for generations.”

Catherine Vautrin, the French Minister of the Armed Forces and Veterans, said: “Having independent nuclear forces does not exclude coordination. Our nuclear cooperation with the United Kingdom keeps deepening: on Tuesday night, UK Typhoons participated for the very first time to a French nuclear exercise alongside Rafales.

“Through coordination, our nuclear forces demonstrate that they can contribute even more significantly to the overall security of the Alliance and to the peace and stability of the Euro Atlantic area.”

The exercise falls under the Northwood Declaration, the agreement signed last year under which the two countries said that no extreme threat to Europe could arise which would not prompt a response by both, while each retains sovereign and independent nuclear forces and national decision making. Britain and France are the only nuclear armed states in Europe, and the declaration established a joint nuclear steering group to coordinate their policy, capabilities and operations.

Saint-Dizier is the base of the 4th Fighter Wing, which operates Rafales carrying the ASMP-A supersonic stand-off missile that forms the airborne half of the French deterrent. The French maintain both an airborne component and ballistic missile submarines, while Britain has relied on submarines alone since the WE.177 bomb was withdrawn in 1998.

That changes with the purchase of twelve F-35A aircraft and British entry into NATO’s nuclear mission, which will return a nuclear role to the Royal Air Force after more than a quarter of a century. Air Marshal Johnny Beck told a committee this year that the aircraft were not bought for the nuclear role, while the government has presented the purchase as the means of joining the mission.

The Defence Investment Plan commits £63 billion over four years to the nuclear enterprise, funding the Dreadnought ballistic missile submarines, SSN-AUKUS attack submarines, a new sovereign warhead and the supporting infrastructure. The refreshed Lancaster House agreement between Britain and France covers an expanded joint deployable force, deeper nuclear cooperation and work on the next generation of weapons.