The EU and U.K. need to ban all Russian aircraft from overflying its airspace.
The UK has more to lose if this course of action is taken and Russian Federation retaliates.
It would almost double the distance between the UK and north Asia (e.g Heathrow-Tokyo/Hong Kong/Shanghai/Seoul etc.) if aircraft were banned from Russian airspace and had to fly via Cairo, Bombay, and Bangkok, as was the case in the "bad old days" before the 1980s. It would add a great deal of fuel expenditure and could mean the end of non-stop flights.
May not happen as Russia earns a lot revenue from these flights. Banning UK flights from Russian airspace would have a far bigger impact than vice versa.