Sir Keir Starmer welcomed the Sultan of Brunei to Downing Street to renew a deal that allows the UK to have a permanent army garrison in the country.
The Garrison Agreement is renewed every five years.
Sir Keir greeted Sultan Haji Hassanal Bolkiah at the door of No 10 and then held a meeting with him in the White Room.
They discussed the ceasefire in Lebanon and the need to secure a similar arrangement in Gaza, Downing Street said.
They also talked about deepening their economic cooperation through trade, tourism, education and clean energy.
Sir Keir said he hoped the UK’s accession to the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP), which Brunei is a member of, would boost growth.
Britain became a member of the Indo-Pacific trading bloc on Sunday.
UK officials have said that joining could boost the economy by as much as £2 billion a year compared with levels of GDP projected for 2040 without the deal.
