[Poohbah]

If I were leading a British government that opted to secede, I'd simply make "an offer that can't be refused" to the other EU states.

"Vote against our leaving on our terms, and we will use our Trident submarine force against your nations."

NOBODY would want a piece of that.

The only problem is that the French would insist on seceding with you as your vassal state.

[Poodlebrain]

What makes you think the Tident submarines would have British crews when such decision to secede would be made?

The draft constitution clearly mentions federal primacy in metters of foreign relations and defense. Surely one of the first actions of the new government will be to consolidate control of all nuclear weapons at the highest levels.

They would have a much better chance of seceding by asking the U.S. for assistance and some sort of alliance, maybe even statehood.