[petre]

The UK has already done it.

"The UK has suspended the operating permit for Belarusian state airline Belavia, and EU leaders have called on member states to take similar action."

https://www.bbc.com/news/world-europe-57236489

[teachingassist]

Given that Minsk to London Gatwick is Belavia's furthest west flight (B2851, three times per week), this has limited effect.

Belavia has no reason to fly over UK airspace otherwise.