The Russian Ambassador was summoned for a meeting to revoke the accreditation of a Russian diplomat.
An FCDO spokesperson said:
"We condemn in the strongest possible terms Russia's unprovoked and unjustified decision to expel a British diplomat last month and its baseless accusations against our staff.
"Summoning the Russian Ambassador, a senior FCDO official made it clear that the UK will not stand for intimidation of British Embassy staff and so we are taking reciprocal action today, revoking the accreditation of a Russian diplomat.
"It is deeply disappointing that Russia continually seeks to disrupt the work of the UK's diplomatic missions and deter our support for Ukraine. Any further action taken by Russia will be considered an escalation and responded to accordingly."
