Foreign Secretary Lord Cameron wants to encourage Nato allies to “step up and spend more on defence” in the face of Russian aggression.

As the alliance celebrates 75 years since its founding, Lord Cameron is expected to reinforce that Nato has never been stronger, more united, or more relevant than it is today.

At a Nato foreign ministers’ meeting on Wednesday, the former prime minister hopes to sign allies up to British-led initiatives to buy Nato standard missiles and munitions for the Ukrainian armed forces.

Lord Cameron said: “Seventy five years after its creation, we are celebrating a Nato that has never been stronger or more important, especially following Sweden’s accession last month.

“With Ukraine closer to Nato than ever, we must sustain the critical support Ukraine needs to win the war.

“Allies need to step up and spend more on defence in the face of continued Russian aggression and a more dangerous world.”

The Conservative peer will welcome Swedish foreign minister Tobias Billstrom to Nato after Sweden’s historic accession to the alliance last month.

This year marks 10 years since allies committed to invest at least 2% of their GDP on defence spending, at the Nato Summit in Wales.

The Foreign Office said all allies are in agreement that Ukraine will join Nato and the UK will continue to push for progress on the country’s membership.