Sir Keir Starmer has said “we need to double down” on support for Ukraine as it was reported Joe Biden has given the green light to Kyiv to use US-supplied long-range missiles to strike inside Russia.

The Prime Minister pledged that Ukraine was “top” of his agenda at this week’s G20 summit of world leaders and told reporters that “there’s got to be full support as long as it takes”.

There has been concern about the level of support the US may continue to give Ukraine when President-elect Donald Trump returns to the White House in January.

President Mr Biden has authorised the use of US-supplied long-range missiles by Ukraine to strike inside Russia for the first time, AP has reported, citing a US official and three people familiar with the matter.

The decision would mark a major US policy shift as Mr Biden is about to leave office.

Earlier this week, German Chancellor Olaf Scholz spoke to Mr Putin in what was the Russian leader’s first publicly announced conversation with the sitting head of a major western power in nearly two years.

Asked if he had any plans to make a similar call, Sir Keir said: “It’s a matter for Chancellor Scholz who he speaks to. I have no plans to speak to Putin.”

Speaking to reporters on the way to the G20 summit in Brazil, the Prime Minister added: “We are coming up to the 1,000th day of this conflict on Tuesday.

“That’s 1,000 days of Russian aggression, 1,000 days of huge impact and sacrifice in relation to the Ukrainian people and recently we’ve seen the addition of North Korean troops working with Russians which does have serious implications.

Emergency services personnel work to extinguish a fire following a Russian rocket attack on Ukraine
Emergency services personnel work to extinguish a fire following a Russian rocket attack on Ukraine (Ukrainian Emergency Service via AP)

“I think on one hand it shows the desperation of Russia, but it’s got serious implications for European security […] and for Indo-Pacific security and that’s why I think we need to double down on shoring up our support for Ukraine and that’s top of my agenda for the G20.

“There’s got to be full support as long as it takes and that certainly is top of my agenda, shoring up that further support for Ukraine.”

It comes after Russia made a large-scale attack on Ukraine on Sunday, with President Volodymyr Zelensky saying that Russia launched a total of 120 missiles and 90 drones.