The Defence Secretary will call for a “50-day drive” to arm Ukraine when he chairs a meeting of Kyiv’s allies on Monday.

John Healey is expected to argue that the West should again boost its military support for Ukraine in an effort to bring Vladimir Putin to the negotiating table.

Donald Trump has already threatened to impose “very severe” tariffs on Russia if it does not agree to a ceasefire by September 2, 50 days on from the US president’s announcement that he would sell “top-of-the-line” weapons to Nato that could then be given to Ukraine.

On Monday, Mr Healey will use a meeting of the Ukraine Defence Contact Group (UDCG) to back Mr Trump’s proposal and pledge that the UK will “play our full part in its success to bolster Ukraine’s immediate fight”.

Calling for more support from Western allies, he is expected to say: “Alongside this, the US has started the clock on a 50-day deadline for Putin to agree to peace or face crippling economic sanctions.

“As members of the Ukraine Defence Contact Group, we need to step up in turn with a ‘50-day drive’ to arm Ukraine on the battlefield and force Putin to the negotiating table.”

Monday will be the fourth time Mr Healey has chaired the UDCG, and the third occasion he has done so alongside German defence minister Boris Pistorius.

The group, which brings together defence ministers and officials from Ukraine’s allies, was chaired by the US until Mr Trump came to power and began rowing back on American support for Kyiv and European security.

Mr Healey’s comments come as the Ministry of Defence confirmed the UK had sent £150 million worth of air defence missiles and artillery rounds to Ukraine in the past two months.

The deliveries are part of a commitment to spend £700 million on air defence and artillery ammunition for Ukraine this year, alongside other funding to provide more of the drones that have become key weapons in the war with Russia.