On the other hand it would be fair if a second non-binding referendum without concrete ideas on the conditions with a simple majority for a win could lead to a re-entry. After that the britains can start to become reasonable and implement a 2/3 threshold.
The day you get 2/3 of Brits to vote for joining the EU, that can probably happen. No more geopolitical decisions decided on fumes.
On the other hand it would be fair if a second non-binding referendum without concrete ideas on the conditions with a simple majority for a win could lead to a re-entry. After that the britains can start to become reasonable and implement a 2/3 threshold.