Brexit and its Consequences: Anglo-Japanese Relations in a Post-EU Referendum World (John Nilsson-Wright, Kiichi Fujiwara, Chatham House)

Substantial discrepancies in immediate strategic interests suggest that cooperation between the UK and Japan, if it is to take place, is likely to be modest in nature and should build on existing bilateral security accords.

https://www.chathamhouse.org/publication/brexit-and-its-consequences-anglo-japanese-relations-post-eu-referendum-world