The UK’s permanent representative to the United Nations has accused Russia of bringing about “wild, completely baseless and irresponsible conspiracy theories”.

It came as the UN security council met at Russia’s request to discuss claims levelled by Moscow about biological activities in Ukraine.

Dame Barbara Woodward said Russia must not be allowed to “abuse its permanent seat” on the council “to spread disinformation and lies”.

“Russia has today brought into the security council a series of wild, completely baseless and irresponsible conspiracy theories,” she said.

“Let me put it diplomatically: they are utter nonsense.”

She added: “We do not sit in this chamber to be an audience for Russia’s domestic propaganda.

“And we should not allow Russia to abuse its permanent seat to spread disinformation and lies and pervert the purpose of the security council.”

Earlier, Prime Minister Boris Johnson expressed fears Russia was spreading a “fake story” that the US or the Ukrainians had chemical weapons in Ukraine as a pretext for an atrocity.