Sir Keir Starmer will meet Chinese President Xi Jinping at the G20 summit in Brazil, Downing Street has confirmed.

He will be the first British prime minister to meet the Chinese leader in more than half a decade when they hold talks in Rio de Janeiro on Monday, and has pledged to have “serious, pragmatic discussions” when they speak.

The Xi meeting will be one in a series of discussions the Prime Minister is expected to have with world leaders at the two-day summit, with conflicts in Ukraine and the Middle East likely to be high on the agenda.

Reports that Joe Biden has given the green light for Ukraine to use US-supplied long-range missiles to strike inside Russia emerged on Sunday evening ahead of the summit getting under way.

China’s economy is obviously the second biggest in the world. It’s one of our biggest trading partners and therefore I will be having serious pragmatic discussions with the president when I meet him

Speaking to reporters on the way to the summit on Sunday, Sir Keir said: “I am planning to have a bilateral with President Xi at the G20. I think that’s important.

“We are both global players, global powers, both permanent members of the security council and of the G20.

“China’s economy is obviously the second biggest in the world. It’s one of our biggest trading partners and therefore I will be having serious pragmatic discussions with the president when I meet him.”

Trade could be one of the issues that comes up for discussion amid concern over US President-elect Donald Trump’s threats to impose tariffs on imports.

Sir Keir will be the first UK prime minister to meet the Chinese premier since Theresa May in 2018.

Asked if he wanted a better relationship with Beijing than previous governments, Sir Keir added: “Given the size of the economy it is very important that we have a pragmatic and serious relationship and that’s what I intend to pursue.”

Foreign Secretary David Lammy visited China in October and pledged that the Government would bring “consistency” to the UK’s relations with the country.

He said that there had not been “sufficient contact” between London and Beijing under his predecessors, particularly on human rights issues.

Sir Keir is expected to arrive in Rio in the early hours of Monday morning UK time.

It is thought that he will call on leaders to go further and faster in their support for Ukraine and warn of “unfathomable consequences” if Putin succeeds.

While Sir Keir was on his way to the summit, AP reported that President Biden has authorised Ukraine’s use of US-supplied long-range missiles to strike inside Russia for the first time.

The move marks a major policy shift as he is about to leave office and comes ahead of the 1,000-day mark since Russia’s invasion of Ukraine on Tuesday.

The two-day summit is the first visit to Brazil by a UK prime minister for 12 years and it is thought that Sir Keir will focus on conversations that could help increase economic growth and security at home and abroad.

In a statement ahead of the summit, the Prime Minister said: “It is in the UK’s best interests to engage on the global stage – whether that’s building strong and fruitful partnerships with our closest allies or being frank with those whose values differ from our own.

“Close cooperation with the world’s leading economies is vital to secure investment into the UK, and create the jobs needed to catalyse growth.

“As we mark 1,000 days since Putin’s illegal invasion of Ukraine, I will be doing all I can to bolster Ukraine as they continue to bravely defend their sovereignty.

“Under my leadership, the UK will be a responsible actor at a time of increasing volatility in the world, while ensuring our diplomacy delivers for people at home.”