UK defence obligations to South Korea

The rapid advancement of North Korea’s nuclear weapon and missile capabilities during 2017 has heightened fears of a military escalation. The prospect of a war in the Korean Peninsula, and how one might unfold, has given rise to questions about how the UK might respond.

The UK has no treaty obligations to come to the defence of South Korea if it is attacked.

However, it has made a strong – but not automatic – commitment to take part in resisting renewed aggression.

The UK fought in the 1950-53 war as part of the 16-nation strong US-led United Nations Command force. The 16 nations signed a Joint Declaration Concerning the Korean Armistice in 1953 on the same day as the Armistice Agreement. The Declaration says: “if there is a renewal of the armed attack, we should again be united and prompted to resist.”

The Government at the time made it clear this is not an automatic commitment to get involved in any renewal of hostilities, a view reaffirmed by the Government in 2006.

The UK remains a member of United Nations Command, which oversees the armistice, has two permanent staff posts to UNC in South Korea and participates in annual exercises.

The United States has a separate treaty commitment to help South Korea defend itself under the 1953 Mutual Defence Treaty. It is widely expected this Treaty would be invoked in the event of hostilities on the peninsula and the US maintains a joint Command with South Korean forces for such an eventuality