EU tried all this bullshit with the UK too. Threatening to cut off electricity supplies and so on. The mask really fell, but in the end they didn't do it, they didn't even respect their own supposed red lines like cooperation on academic research. They meekly invited the UK back into their academic collaboration a few years later despite claiming at the time that it was a "privilege" tied to everything else by the laws of physics. So the idea an organization that weak is going to try and genocide an entire country over FoM is ridiculous.
At any rate, there's nothing about being an island that automatically stops a crazy genocidal EU trying to starve another country. If I recall history correctly, less than 100 years ago a big European country was attempting to starve Britain to death by systematically sinking its cargo convoys. Then just a few decades later east Germany was trying to starve Berlin by shutting down rail links. Note: both attempts failed.