The article examines the state, activity and ideology of left-wing autonomist and separatist parties in Britain and France. The authors compare their experience and come to the conclusion that the separatist trend prevails in the UK, whereas in France the autonomist one is more popular. The Scottish National Party as a ruling party in the region stands for Scotland’s independence from the United Kingdom, the country’s integration to the EU and active membership in NATO. The Party of Wales also shares a separatist view. It strives for the integration of Wales into the EU in the long term and does not put NATOrelated issues on the agenda. Sinn Féin, active both in the Republic of Ireland and Northern Ireland, supports the Irish unification. Moreover, it is Eurosceptic and Atlanticsceptic that is manifested in a desire to reform the European Union and limit Ireland’s participation in NATO-related structures. At the same time foreign policy for French regionalists is not a central topic in their manifestos. For the most part, wanting to remain part of France, the autonomists focus on local issues. Membership in the European Free Alliance and commitment to the project called Europe of the Regions are characteristic of all the parties under consideration, with the exception of Sinn Fein. Due to their commitment to the principles of democracy, equality, solidarity, environmentalism and inclusivity, these parties belong to the European left movement. The research is based on official party documents, commentaries provided by politicians and academic literature on the topic. © 2025 Elsevier B.V., All rights reserved.