The Russian Ambassador was summoned for a meeting to revoke the accreditation of a Russian diplomat.
A UK Government spokesperson said:
We strongly condemn Russia’s unjustified decision last month to expel another British diplomat and the malicious public smear campaign that followed. This behaviour is wholly unacceptable, and we will not tolerate harassment or intimidation of our diplomatic staff.
We have therefore summoned the Russian Ambassador to announce we are taking reciprocal action, revoking the accreditation of a Russian diplomat.
Russia’s repeated unprovoked and unjustified actions are designed to disrupt our diplomatic work and form part of a wider campaign of aggressive behaviour towards the UK.
Any further action by Russia will be treated as an escalation and met with a firm and proportionate response.