Britain and France to lead rehearsal of Ukraine deployment force

The exercise, named Koalicja and running from 9 to 22 November, will rehearse how to move, protect and supply a force in Ukraine and test its command and control to ensure troops from different countries can work together. It follows plans set out last year for a reassurance force as one of the long-term security guarantees European nations proposed for Ukraine.

Western officials stress that any force sent to Ukraine would not take part in offensive operations, peacekeeping or ceasefire-monitoring missions, and would not operate under Nato command or on the front line. Officials say its presence would be to reassure Ukraine and help rebuild its armed forces. The US has been involved in discussions but is not contributing.

UK Defence Secretary Wes Streeting said the exercise showed Britain, France and their allies were stepping up preparation for the day when peace came to Ukraine. "This is not a hypothetical plan, it's a real force, ready to help Ukraine once the fighting stops."

Lt Gen Tom Bateman, the UK commander of the Multi National Force - Ukraine (MNF-U), said the exercise represented an important step in translating political commitments into credible military readiness, describing it as a "real, capable, readily deployable force that represented a serious commitment from Coalition of the Willing nations to Ukraine's long-term stability and security".

Some 2,800 personnel will take part across land, sea and air. The UK contribution includes 300 troops and a pair of RAF Typhoons, with fighter jets simulating how they would reassure commercial aircraft once Ukraine's skies can be reopened. Turkey has agreed to lead the maritime mission, with the eventual goal of clearing mines and allowing the resumption of Black Sea trade.

Russia has already voiced opposition to foreign troops being stationed in Ukraine, and last year President Vladimir Putin said they would be "legitimate targets". Western officials have declined to spell out the rules of engagement if such troops were attacked, though they say the force would be able to defend itself.

Western officials could not comment on the final make-up and shape of any force that might deploy, and officials acknowledge that commitments and contributions will depend on the circumstances of a cessation of hostilities and individual nations' political decisions. Military experts have suggested Western nations might have to send tens of thousands of troops to guarantee Ukraine's security. It is also unclear what training role Western forces could provide to battle hardened Ukraine, whose soldiers are already in high demand training Nato forces, passing on their expertise in drone warfare. Russia, meanwhile, has shown no sign of wanting to end its war.