Athens didn't let member states quit the Delian League ...

Athens didn't let member states quit the Delian League. Abe Lincoln didn't let member states quit the United States. You could have known the European Commission would be unwilling to let Great Britain leave the EU.

The Economist has an article today -- From Brussels with love ... The multi-billion-euro exit charge that could sink Brexit talks ... A bitter argument over money looms:

... officials in Brussels are drawing up a bill for departure that could mean Britain’s contributions remain close to its membership dues for several years after it leaves...
Michel Barnier, who will lead negotiations on behalf of the commission, is said to consider that the bill stands between €40bn and €60bn.

Fuck'em.

Article 50 says
1. Any Member State may decide to withdraw from the Union ...
2. A Member State which decides to withdraw shall notify the European Council ...
3. The Treaties shall cease to apply to the State in question from the date of entry into force of the withdrawal agreement or, failing that, two years after the notification referred to in paragraph 2 ...

I didn't make it up. You decide to withdraw, you tell 'em, and in two years (or less) you're out. There's nothing in there about 60-billion-euro exit fees.

Worst case? Wait 'em out.