The UK and South Korea are set to sign a new long-term agreement covering defence and technology co-operation as President Yoon Suk Yeol arrives for a three-day state visit.

The Downing Street Accord follows similar agreements with Singapore and Japan, coming as the UK seeks to consolidate influence in the Indo-Pacific.

Mr Yoon begins his state visit on Tuesday, which will include a bilateral meeting with Prime Minister Rishi Sunak and the formal signing of the agreement in Downing Street on Wednesday.

Ahead of the visit, Mr Sunak pointed to the £21 billion which South Korean businesses commit in investment to the UK.

Trade and investment are expected to be the focus of the trip, with Trade Secretary Kemi Badenoch set to launch new negotiations on an upgraded free trade agreement.

The UK secured a free trade deal with South Korea in 2019, with the agreement largely aimed at keeping trade flowing post-Brexit and removing uncertainty.

Mr Sunak said: “Long term, global partnerships are vital to our prosperity and security, both today and in the future. As two nations focused on innovation, harnessing new technologies and defending the international rules-based order, the UK and Republic of Korea are natural partners.

“Through our new Downing Street Accord, we will drive investment, boost trade and build a friendship that not only supports global stability, but protects our interests and lasts the test of time.

“These close ties have already propelled £21 billion of investment between our countries.

“I know a free trade agreement fit for the future will only drive further investment, delivering on my promise to grow the economy and support highly-skilled jobs.”

The Downing Street Accord will see British and Korean militaries agree to step up joint training and operations, with the Asian state expected to agree to join with British ships on sanctions patrols.

It will, Downing Street said, also see the two countries work closer together on technology such as artificial intelligence, semi-conductors and quantum.

Science ministers will also sign a memorandum of understanding to boost space co-operation.

South Korea will host next year’s AI summit after the first UK-backed gathering in Bletchley Park earlier this month.

The trip to the UK coincides with the 140th anniversary of diplomatic relations between the UK and Korea, as well as the 70th anniversary of the armistice of the Korean war.