Russia’s ambassador has been summoned to the Foreign Office over an “unprecedented and unfounded public campaign of aggression against the UK”, the Government has said.

A Foreign Office spokesperson accused Russia of making “malicious and completely baseless accusations” against Foreign Office staff after Moscow alleged six British diplomats had been engaged in spying and sabotage last week.

The spokesperson said: “This pattern of behaviour is completely unacceptable, deeply unprofessional, and beneath the standards of conduct between states.

Russia must stop this activity immediately

“This is the latest development in a deliberate campaign by Russia to undermine and threaten UK security and democracy and deter our support for Ukraine, through disinformation, acts of sabotage in Europe and direct harassment and restrictions against our diplomatic missions in Russia. This campaign will not succeed.

“Russia must stop this activity immediately.”

Russia revoked the diplomatic accreditation of six members of staff working at the British Embassy in Moscow on September 13 after its security service, the FSB, claimed it had found “signs of spying and sabotage”.

The Foreign Office said the allegations were baseless, and in a statement on Wednesday said the move was “in direct contravention to Russia’s obligations under the Vienna Convention on Diplomatic Relations”.

The incident is the latest in a series of diplomatic rows between Britain and Russia over the past year.

In May, the UK expelled Russia’s defence attache in London, Colonel Maxim Elovik, claiming he was an “undeclared military intelligence officer”, removed diplomatic status from several Russian-owned premises, and placed restrictions on Russian diplomatic visas.

In response, Russia expelled Britain’s defence attache in Moscow, Captain Adrian Coghill.