Rishi Sunak has said new support measures for Ukraine agreed between the UK and France are designed to put Kyiv in the “strongest possible position” to negotiate a ceasefire.

The Prime Minister and French President Emmanuel Macron used the UK-France summit to sign off on jointly training Ukrainian marines and supplying weapons to the country in its fight against Russia’s invading forces.

During a press conference in Paris, the leaders said the immediate priority was to bolster Ukrainian President Volodymyr Zelensky’s forces and allow them to “mount a successful counter-offensive”.

Mr Sunak announced in February, during Mr Zelensky’s visit to Britain, that the UK would start to train Kyiv’s marines as well as pilots.

Friday’s declaration from the summit at the Elysee Palace will see France join Britain in preparing marines for the drive to purge Ukraine of Russian troops.

Mr Sunak said the agreement would “help to give Ukraine a decisive advantage on the battlefield and for Ukraine to win this war”.

He argued that a successful counter-punch would allow the Ukrainians to enter any potential future negotiations with Moscow from a position of strength.

“In regards to the future, that is a decision for Ukraine, not a decision for us to make for them,” he said.

“Our job is to put Ukraine in the strongest possible position, and that is what our conversations today have been about.

“The announcements you’ve seen from us today around training marines, helping with the provision of ammunition, are very tangible examples of our commitment to deliver Ukraine that advantage.

“And that’s where our focus is going to be over the coming weeks and months.”

Mr Sunak was asked during his trip on the Eurostar to the French capital whether he agreed with Mr Macron’s statement that Ukraine should start peace negotiations in the summer.

Speaking to reporters, the Prime Minister said the French leader had recognised at the Munich security conference last month that “now is not the time for negotiations”, with the West’s focus on strengthening Ukraine’s battlefield operations and defending its critical national infrastructure.

He continued: “Of course, this will end as all conflicts do, at the negotiating table, but that is a decision for Ukraine to make.

“And what we need to do is put them in the best possible place to have those talks at an appropriate moment that makes sense for them.

“But at the moment, the priority has got to be giving them the resources, the training and the support they need to push forward and create advantage on the battlefield.”

As well as the accord on re-arming Ukrainian forces and training marines, London and Paris also agreed to collaborate to develop precision strike weapons to combat Russian aggression in Europe.

Downing Street said no timeframe had been set for when the Ministry of Defence (MoD) hoped the weapons could be operational.

The first Anglo-French summit since 2018 also saw a plan unveiled for increased allied activity in the Indo-Pacific.

No 10 said it will include establishing France and the UK as the “backbone” to a permanent European maritime presence there.

The approach will include co-ordinating regular deployment of France’s Charles de Gaulle aircraft carrier and the UK’s HMS Queen Elizabeth and HMS Prince of Wales carriers.

Discussions between Defence Secretary Ben Wallace and his French counterpart also involved further integration of the UK and French armed forces, intelligence sharing and future interoperability of weapons, according to the MoD.

“We have agreed to strengthen our defence and security partnership, committing to look at areas of cooperation to increase the interoperability of our joint defence capabilities – and to advance key projects to develop complex weapons systems,” Mr Wallace said.

It comes ahead of an update to the integrated review on foreign and security policy, which Mr Sunak will announce on Monday during a visit to the US.

The update is expected to deliver new wording on Britain’s approach to China after calls from senior Conservatives for a more hawkish view of Beijing.