Downing Street has denied allegations that a British diplomat expelled from Russia was a spy.

Russian state-run news agencies reported that the country's security service FSB accused the diplomat - whose photo was shared on Russian TV bulletins - of providing false information on his documents and carrying out espionage activities.

When asked if a tit-for-tat expulsion would occur, a No 10 spokesman said they were "considering" their response.

"To be clear, we refute these allegations" he said, calling them "baseless."

Russian foreign ministry spokeswoman Maria Zakharova said the ministry had also summoned the British ambassador, Tass news agency reported.

Footage shows the British ambassador's car pulling up to the Ministry of Foreign Affairs in Moscow.

According to Tass, the FSB says that the diplomat was a replacement for one of six UK diplomats expelled in August, also on espionage charges.

"This is not the first time that [Vladimir] Putin's government has made malicious, baseless accusations against our staff," Downing Street said.

"The UK government is unapologetic about protecting our national interests and will now respond in due course, and our embassy in Moscow will continue its important work in Russia to support UK interests."

It comes amid worsening relations between the UK and Russia since the latter's full-scale invasion of Ukraine in 2022.

Last week it emerged the UK lifted restrictions on Ukraine using British-supplied Storm Shadow missiles on targets inside Russia for the first time.

President Vladimir Putin cited the move, alongside the launching of US-supplied longer-range missiles at Russian territory, as being behind Russia's decision to launch a new hypersonic missile at the Ukrainian city of Dnipro on Thursday.

Expulsions of diplomats have become increasingly common since the war began.

Earlier this year, British diplomat Capt Adrian Coghill was given a week to leave Russia, days after the Russian defence attaché was expelled from London for alleged espionage as an "undeclared military intelligence officer".

More British politicians and press have also been barred from entering the country.

On Tuesday, Russia added 30 more to their "stop list" for what it called "hostile actions".

Included in the list are: Deputy Prime Minister Angela Rayner, Home Secretary Yvette Cooper, Chancellor Rachel Reeves, and Justice Secretary Shabana Mahmood.

Russia has previously banned British politicians and journalists, including from the BBC, Sky News and Channel 4.

In 2022, it banned now Prime Minister Keir Starmer and Foreign Minister David Lammy, among other senior government officials. Leader of the Conservative party Kemi Badenoch was also banned in the same year.