Britain is already in neither; it's never been in Schengen, and left the EFTA when joining the EEC as the EU was then. Although the other 3 countries in EFTA a

Britain is already in neither; it's never been in Schengen, and left the EFTA when joining the EEC as the EU was then. Although the other 3 countries in EFTA are part of the EEA (edit: which is how they're part of the single market), Switzerland isn't. Instead, they participate in the single market via a bunch of bilateral treaties: https://en.wikipedia.org/wiki/Switzerland%E2%80%93European_Union_relations https://en.wikipedia.org/wiki/Switzerland%E2%80%93European_U...