The European Union last month approved a 90-billion-euro ($118 billion) loan Ukraine desperately needs to plug a budget shortfall after Hungary lifted its veto.

"We are discussing participating" Starmer said of the loan, addressing reporters as he arrived at a summit of European leaders in Armenia.

Under the loan scheme, Ukraine will only pay back the money once Moscow pays for the damage President Vladimir Putin's invasion has wrought -- with Brussels to cover interest costs through the EU budget.

EU countries agreed in February Ukraine could use the loan to buy a greater share of weapons from close allies like Britain, if those countries contributed financially, covering some of the borrowing costs.

That came after weeks of haggling, with France that had pushed for tough limitations on purchases from outside the EU, while others argued for a more lenient stance towards partners such as Britain, Canada and Norway.

The loan scheme allows Ukraine to spend 60 billion euros on weapons to fight Russia's invasion.

Starmer said British participation would give Ukraine the "capability that it desperately needs" as Russia's war grinds into a fifth year and would boost UK jobs.

Ties with Brussels would also benefit, he added.

In a joint statement after bilateral talks in Yerevan, Starmer and European Commission chief Ursula von der Leyen said the move would represent "a major step forward in the EU-UK defence industrial relationship".

Kyiv had been pushing the EU to let it buy weapons from wherever it needs.

"We are beginning negotiations with the EU to ensure Ukraine gets the equipment it needs to defend its freedom, while driving opportunities for British industry to play its full part," Starmer said.

Pressure for stronger UK-EU ties has grown as US President Donald Trump rocks Washington's long-time allies by throwing transatlantic relations into doubt.

The loan talks come after British efforts to increase involvement in a separate 150-billion-euro weapons programme last year sunk after London baulked at the size of a proposed entry fee.