On Thursday, Boris Johnson announced that the UK would send a further 6,000 missiles and £25 million to the Ukrainian military.

In calls with the Prime Minister, Volodymyr Zelensky has repeatedly requested more aid and weapons, despite rising hopes of a peace deal, a Downing Street source said.

Ms Truss’s push for more funding for Ukraine came after Mr Sunak was criticised for failing to increase the UK’s defence budget in Wednesday’s Spring Statement.

Tobias Ellwood, the chairman of the Commons defence select committee, told The Telegraph that the Spring Statement should have been used to “send a message to [Vladimir] Putin that we take European security seriously”.

“There is a direct link between the domestic difficulties we face and European security. We have missed a trick in not recognising the Government’s first duty to the British people,” he said.

A FCDO spokesman said: “We do not comment on private meetings. Our immediate concern is how we help Ukrainians facing a humanitarian crisis now.

“The UK is at the forefront of these efforts, supporting those fleeing Ukraine as a result of Putin’s unprovoked aggression and continues to lead with economic and humanitarian support totalling £400 million.

“We have deployed humanitarian teams to the wider region to ensure essential supplies and medical support reach those who need it most.”