Russian Foreign Minister Sergei Lavrov has hit back at Theresa May and Defence Secretary Gavin Williamson over allegations the country poisoned an ex-spy with a powerful nerve agent on British soil, saying the Kremlin has "stopped paying attention".

The attack on Sergei Skripal, 66, in an Italian restaurant in Salisbury and the PM's subsequent decision to expel Russian diplomats from the UK, backed by Western powers, has greatly angered Moscow ahead of the country's forthcoming presidential election this Sunday.

Speaking at a summit on the Syria crisis in Kazakhstan, Mr Lavrov was asked by reporters whether President Vladimir Putin's government intended to dismiss British diplomats in retaliation. "Of course we will", he replied, but declined to give further details other than to say it would happen "soon".

He also said he considered Ms May's response a violation of international agreements, according to Reuters.

He also turned his fire on Mr Williamson, who yesterday suggested that Russia should "go away and shut up" by speculating, "Maybe he lacks education."

Back in Moscow, Williamson was the subject of even more severe criticism from defence ministry spokesman Major-General Igor Konashenkov, who likened him to a "market wench" and said he suffered from "extreme intellectual impotency", according to The Daily Mail.

Defence Secretary Gavin Williamson: 'Frankly, Russia should go away, and should shut up'

Skripal and his daughter Yulia, 33, remain gravely ill in hospital after coming into contact with a Russian-made toxin, Novichok, while enjoying Sunday lunch in a branch of Zizzi in the quiet Wiltshire cathedral town two weeks ago.

The US, France and Germany have presented a united front in support of Ms May's handling of the controversy, which has reminded many of the climate of intrigue that abided at the height of the Cold War.

A statement released by US President Donald Trump, French President Emmanuel Macron and German Chancellor Angela Merkel yesterday read:

Theresa May orders biggest expulsion of Russian spies in 30 years in response to Salisbury poisoning

"The United Kingdom briefed thoroughly its allies that it was highly likely that Russia was responsible for the attack.

“We share the UK assessment that there is no plausible alternative explanation, and note that Russia’s failure to address the legitimate request by the UK Government further underlines its responsibility.

“We call on Russia to address all questions related to the attack in Salisbury. Russia should in particular provide full and complete disclosure of the Novichok programme to the Organisation for the Prohibition of Chemical Weapons.”

For its part, Russia's response to the allegations against it has been indignant.

Russia's ambassador to the UK, Alexander Vladimirovich Yakovenko, yesterday described Ms May's expulsion of diplomats as "absolutely unacceptable" and "a provocation" and urged her to "follow international law".

Moscow's envoy to the UN, Vasily Nebenzya, responded to Britain giving his country a 24-hour deadline to answer the poisoning accusations earlier this week by saying Russia "does not speak the language of ultimatums" and protesting that it had been asked to confess without being given the opportunity to carry out its own investigations.

Salisbury attack: Timeline of events

Theresa May continued the war of words by telling Parliament: "Their response demonstrated complete disdain for the gravity of these events.

"They have treated the use of a military-grade nerve agent in Europe with sarcasm, contempt and defiance."

Skripal attack aftermath – in pictures Show all 15 1 /15 Skripal attack aftermath – in pictures Skripal attack aftermath – in pictures Scene of attack Members of the emergency services in hazard suits fix the tent over the bench where Sergei and Yulia Skripal were found unconscious on a park bench in Salisbury in March 2018. Getty Skripal attack aftermath – in pictures Victim - Sergei Skripal The retired Russian colonel and former double agent for MI6 was in a critical condition in hospital for more than two months after being exposed to novichok in Salisbury. He was given refuge in the UK after being jailed in Moscow for treason. Mr Skripal came to Britain as part of a high-profile “spy swap” in 2010 in which four men were exchanged for ten Russian "sleeper agents" in the US. In this image he is speaking to his lawyer from behind bars in Moscow in 2006. AP Skripal attack aftermath – in pictures Victim - Yulia Skripal Yulia Skripal was struck down by a novichok poison alongside her father Sergei. Facebook Skripal attack aftermath – in pictures Scene of attack A police officer stands guard outside a branch of the Italian chain restaurant Zizzi where the pair dined at before falling ill. It was boarded off whilst investigators worked on the building and later found traces of the chemical weapon within it. AFP/Getty Skripal attack aftermath – in pictures Scene of attack Large areas of central Salisbury were cordoned off by police following the discovery of the Skripals. Traces of nerve agent were also found in The Mill pub. PA Skripal attack aftermath – in pictures Victim - Nick Bailey Detective Sergeant Nick Bailey, rushed to the aid of the Russian ex-spy and his daughter who were targeted with a nerve agent. He was hospitalized after aiding them and didn't leave until three weeks after the attack. Wiltshire Police/Rex Skripal attack aftermath – in pictures Police investigation - Skripal’s home Police believe they were poisoned at home, and detectives found the highest concentration of novichok on the front door of Mr Skripal’s house. Getty Skripal attack aftermath – in pictures Theresa May visits scene of attack Britain's Prime Minister Theresa May spokes with Wiltshire Police's Chief Constable Kier Pritchard near where the Skripal's were found. Britain expelled 23 Russian diplomats over the nerve agent poisoning and suspended high-level contacts, including for the World Cup on March 14. Theresa May told parliament that Russia had failed to respond to her demand for an explanation on how a Soviet-designed chemical, Novichok, was used in Salisbury. AFP/Getty Skripal attack aftermath – in pictures Skripal days before attack Sergei Skripal days before he was exposed to Novichok, that has left him fighting for life. ITV News Skripal attack aftermath – in pictures Police investigation - military involvement British soldiers were deployed soon after the attack to help a counter-terrorism investigation into the nerve agent attack. One of the places they were asked to help out with was Skripal's home and it's surrounding. They were asked to remove a vehicle connected to the agent attack in Salisbury, from a residential street in Gillingham. AFP/Getty Skripal attack aftermath – in pictures Police investigation Personnel in protective coveralls and breathing equipment cover an ambulance with a tarpaulin at the Salisbury District Hospital. AFP/Getty Skripal attack aftermath – in pictures Police investigation The investigation extended to the grave of Sergei Skripal's son Alexander in London Road cemetery. Getty Skripal attack aftermath – in pictures Police investigation The Counter Terrorism Policing Network requested assistance from the military to remove a number of vehicles and objects from Salisbury. EPA Skripal attack aftermath – in pictures Home Secretary visits scene of attack Home Secretary Amber Rudd visited the scene of the nerve agent attack at the Maltings shopping centre on 9 March. Getty Skripal attack aftermath – in pictures Yulia Skripal speaks for the first time Yulia Skripal, speaking for the first time, said she felt lucky to have survived the nerve agent attack in Salisbury which left her fighting for life. Ms Skripal said her life had been “turned upside down” by the assassination attempt. But the Russian national added she hoped to return to her homeland one day, despite the Kremlin being blamed for the attack. Reuters

Ms May visited Salisbury yesterday to meet with emergency services personnel and forensic investigators pursuing the Skripal affair.