British fighter planes visiting Japan will fly over the South China Sea and Britain will sail aircraft carriers in the Pacific once they are operational in 2020, given concerns about freedom of navigation there, Britain's ambassador to the United States said on Thursday.

The envoy, Kim Darroch, told a Washington think tank that British Typhoon aircraft currently deployed on a visit to Japan would fly across disputed parts of the South China Sea to assert international overflight rights, but gave no time frame.

Speaking at an event also attended by Japan's ambassador to Washington, Darroch said that most future British defense capacity would have to be directed toward the Middle East, but added: "Certainly, as we bring our two new aircraft carriers onstream in 2020, and as we renew and update our defense forces, they will be seen in the Pacific.