Europe will be "back at zero" if the UK waters down plans to send a stabilisation force to Ukraine, experts warned last night. It follows claims that London is reconsidering plans to send thousands of troops to protect Ukraine because the risks are deemed “too high”. Instead, the security would be left to a multinational air squadron to police Ukrainian skies while Turkey provides a maritime presence in the Black Sea.

The only NATO boots on the ground would be in the form of French and British trainers, based in the West of Ukraine and far from the frontlines. This move is, in any case, necessary to free up UK training grounds for British Army troops. In the meantime, the focus would be to continue to send weapons and build up Ukrainian forces to ensure they would be in a strong position should Russia break the terms of any deal. Suggestions of a shift in posture - dubbed “mere speculation” by the Ministry of Defence - were revealed to The Times by diplomatic sources involved in discussions about a coalition of the willing.

“The risks are too high and the forces inadequate for such a task,” claimed a source.

The source made it clear that the trainers planted on Ukrainian soil would, under these new measures, simply be there to “reassure” Kyiv and would not be a deterrence or protection force.

It is not the first time that the prospect of turning to “Plan B” has been considered.

Army chiefs, already struggling to fill the ranks against repeated missed recruitment targets, have consistently expressed private reluctance to commit a force of thousands to an enduring operation such as Operation Telic in Iraq, which, even if it could be achieved, would impact on other NATO commitments.

This week, the UK-led battlegroup in Estonia completed exercise Bold Eagle.

The seven-day exercise in Estonia challenged Estonian, French, Polish, UK and US forces’ readiness to navigate the complex, boggy landscape of the northern Baltics.

Last month, the Express warned how it could be left to a multinational squadron of between 18 and 35 Typhoons and F-35 fighter jets, based on NATO airfields, to do the “heavy lifting” in deterring Russia against a third invasion following any peace deal.

The UK already carries Enhanced Air Policing (eAP) patrols on NATO’s flanks, and has committed to sending an additional batch of Typhoons to Poland.

But, with 30 nations already expressing a willingness to contribute to a 30,000-strong stabilisation force, it was hoped that plans for a proper stabilisation force would continue to solidify, and ony be withdrawn at the last minute in return for concrete concessions by Russia.

Diplomatic efforts to secure a peace treaty are proving elusive, with the looming threat from the US that it may give up if Ukraine does not move from its current position.

As things stand, however, Moscow has little incentive to enter into any meaningful peace accord, and Russian President Vladimir Putin is expected to continue to try to gain ground until next year, when the state of the Russian economy and its depletion of Soviet tanks will likely force him to the negotiating table.

“The key concern is whether offering an air and maritime contingent in itself constitutes a meaningful security guarantee,“ said Justin Crump, of Sibylline strategic risk group

“Ukraine has been let down in the past - the Budapest memorandum has now disappeared from the White House website, with President Trump arguing it was just a memorandum and not a defence pact.

"Britain has signed a defence pact with Ukraine, but we had trainers on Ukrainian soil before this started."

He added: "Will the air contingent really engage Russian planes who breach the terms of any peace deal? What will Turkey’s maritime element actually achieve, as it watches Russia take its warships through the straits?

“If these measures don’t come with a commitment to support Ukraine with force in the event that conflict returns, it seems to me that it’s back to zero. It doesn’t achieve anything.”

A Ministry of Defence spokesman said: “This is speculation. Advanced operational planning within the coalition of the willing remains ongoing for options across land, sea and air, and to regenerate the Ukrainian armed forces. In the meantime, we’re continuing to support efforts for peace, while stepping up military support for Ukraine as Putin’s illegal invasion continues.”