I thought the point of Brexit was to change the UK to differ from the EU, but has anything really changed? Is it too late to breenter?
In theory, any new country joining the EU has to switch to the common currency, the Euro, something the UK was able to gain an exemption from while still a member along with Denmark, Sweden and a handful of others, a long time ago when the Euro was first introduced.
This has always been an issue when discussing Scottish independence too, given the SNP have always claimed Scotland could rejoin the EU and keep the pound; the EU has always said otherwise.
> https://economy-finance.ec.europa.eu/euro/enlargement-euro-a...
But to join the Euro, it is a requirement to be a member of ERM II for 2 years, and Sweden argues that that is voluntary, and just haven't done it.
You're right that Denmark has an opt-out, though.