Relationship dossier
France
United Kingdom
Relationship assessment
Substantial security cooperation alongside recurring post-Brexit disputes
France toward United Kingdom
+35France has pursued close defense cooperation with the United Kingdom through the 2010 Lancaster House agreements, including joint military initiatives and nuclear-related cooperation. The 2018 Sandhurst Treaty also established a framework for French-British cooperation on migration management.
United Kingdom toward France
+35The United Kingdom has maintained defense cooperation with France through the 2010 Lancaster House agreements, including joint military initiatives and nuclear-related cooperation. Under the 2018 Sandhurst Treaty, the British government also agreed to cooperate with France on migration management.
Overall relationship
+30The relationship combines durable defense and security cooperation with recurring political disputes. The Lancaster House agreements and Sandhurst Treaty provide concrete frameworks for collaboration, while post-Brexit disagreements over fisheries and Northern Ireland, alongside disputes over Channel migration, have periodically strained relations.
How to read these scores
Scores are rough judgments, not objective measurements or current verification. Directional scores describe government policy and conduct, not public opinion. The overall score is an independent estimate, never an average.
- −100
- Extreme sustained hostility
- −50
- Substantially adversarial
- 0
- Mixed or neutral, supported by knowledge
- +50
- Substantially cooperative
- +100
- Exceptionally close sustained partnership
“Not assessed” means there is no recorded score. Pair existence makes no claim about diplomatic recognition or established relations.
Relationship context
Overview
France and the United Kingdom maintain substantial security and diplomatic cooperation, including through the 2010 Lancaster House agreements and the 2018 Sandhurst Treaty on migration cooperation. Their relationship has also faced recurring disputes over fisheries, post-Brexit arrangements for Northern Ireland, and Channel migration. Cooperation is significant but tempered by these continuing areas of friction.
Areas of tension
- Post-Brexit disputes over fishing access and fisheries management
- Disagreements over post-Brexit arrangements for Northern Ireland
- Recurring disputes over cooperation to manage Channel crossings and migration
Key developments
France and the United Kingdom signed the Lancaster House agreements, establishing frameworks for enhanced defense cooperation.
France and the United Kingdom signed the Sandhurst Treaty, setting out cooperation on migration management.
Major uncertainties
- The current scope and implementation of bilateral defense and migration cooperation are unclear.
- The durability of post-Brexit arrangements for fisheries and Northern Ireland remains uncertain.