Russia today denied ever making the toxic Novichok nerve agent used to strike down a double agent in Britain as it faced a wall of international condemnation.

Deputy foreign minister Sergei Ryabkov said neither the Russian Federation or the Soviet Union had a Novichok weapons programme. He said his country destroyed the chemical weapon stocks it did hold last year.

The claim is the latest defence from Moscow and comes after Britain, the US, France and Germany issued a rare joint statement condemning the assault on Sergei Skripal.

The leaders said there is 'no plausible alternative explanation' to Moscow being involved in the attempted murder of a former spy on UK soil.

Speaking in Salisbury after the declaration was published, Mrs May said: 'This happened in the UK, but it could have happened anywhere and we are taking a united stance against it.'

In the new denial tonight, Mr Ryabkob told the Interfax news agency: 'I want to state with all possible certainty that the Soviet Union or Russia had no programmes to develop a toxic agent called Novichok.

He slammed people 'distributing information that the programme allegedly existed,' an apparent reference to Soviet chemist Vil Mirzayanov, who first revealed the existence of that class of ultra-powerful nerve agents.

The joint statement was released as Prime Minister Theresa May visited Salisbury today

President Emmanuel Macron (pictured right) and German Chancellor Angela Merkel have swung in behind Britain over the nerve agent attack

US president Donald Trump (pictured in the White House last week) has also endorsed the joint statement released today

Mrs May was shown the ongoing investigation in Salisbury at the spot where Sergei Skripal and his daughter Yulia were found

In an excoriating assessment that lays down the gauntlet to Vladimir Putin, the leaders brand the incident an 'assault on UK sovereignty' and a 'clear violation' of laws on chemical weapons use.

At least 131 people could have potentially been in contact with the deadly nerve agent used in Salisbury. They had not yet developed any symptoms but are being monitored via daily phone calls, Wiltshire Police said last night. Deputy Chief Constable Paul Mills also revealed that 46 people have attended hospital with concerns they could have been contaminated but only three – Sergei and Yulia Skripal and Detective Sergeant Nick Bailey – have tested positive. DS Bailey, who was among the first on the scene after the Skripals were found collapsed, was conscious and in a serious but stable condition. Mr Mills said: ‘We have identified 131 people who potentially could have come in contact with the nerve agent.’ Advertisement

The statement said: '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 (OPCW).'

Speaking at the White House, Mr Trump said: 'It certainly looks like the Russians are behind it. We are taking it very seriously.'

The hard line came as Mrs May visited Salisbury to be updated on the investigation, and after Mr Macron moved to quell fears of a split with Britain over the attack.

Following the briefing, Mrs May said: 'What is important in the international arena - and we have taken this into Nato, into the United Nations, take it through into the European Union - is that allies are standing alongside us and saying this is part of a pattern of activity that we have seen from Russia in their interference, their disruption that they have perpetrated across a number of countries in Europe.

'This happened in the UK, but it could have happened anywhere and we take a united stance against it.'

France appeared to break ranks last night, with a government spokesman demanding more 'proof' of Moscow's involvement.

The intervention risked shattering the international tough line against Vladimir Putin, after a string of allies including Angela Merkel and Donald Trump swung in behind Theresa May.

But after speaking to the PM by telephone early this morning, Mr Macron said he had no doubt that Russia was linked to the attempted murders of a former spy and his daughter earlier this month.

'Everything leads us to believe that responsibility is in fact attributable to Russia,' he told reporters.

'I will announce in the coming days the measures that we intend to take.'

Vladimir Putin, pictured at the Kremlin today, has dismissed the idea Russia was involved in the Novichok attack on a former spy

Sergei Skripal remains in critical condition after the nerve agent attack earlier this month (file picture). Boris Johnson (pictured in London today) urged countries to take a stand against Russian aggression

Mr Skripal and his daughter Yulia (pictured) were targeted with the Russian-made Novichok agent on March 4

Army vehicles arrived in the Dorset village of Alderholt today as part of the Salisbury probe

Mrs May speaks to Wiltshire Police Temporary Chief Constable Kier Pritchard (left) today

The comments followed a statement from President Macron's office that attempted to clarify France's position.

'Since the beginning of the week, the United Kingdom has kept France closely informed of the evidence gathered by British investigators and evidence of Russia's responsibility in the attack,' it said.

'France agrees with the United Kingdom that there is no other plausible explanation and reiterates its solidarity with its ally.'

Downing Street said the Prime Minister used their phone conversation to update Mr Macron on the investigation and reprisals she had announced against Russia.

'President Macron said that France completely shares the UK's assessment that there is no plausible explanation other than that Russia was responsible for the attack and he once again expressed his full support for the UK as a close and strong ally,' the spokesman said.

What action has Theresa May announced against Russia? The PM unveiled the fleet of measures being taken against Russia yesterday Theresa May has announced a fleet of tough measures against Russia in the wake of the poisoning of former Russian spy Sergei Skripal and his daughter Yulia. They include: Expulsion of diplomats Britain will expel 23 Russian embassy staff who have been identified as 'undeclared intelligence officers' from the country within a week. This is the biggest expulsion of diplomats since 1971 when Ted Heath kicked 90 Soviet staff out after the UK uncovered a large Communist spy ring. All high-level contacts with Russia will also be suspended in protest. New and tougher anti-espionage laws will be brought forward to help degrade Russia's capabilities in the UK. The World Cup: Ministers and the Royal Family will boycott the football World Cup in Russia this summer. Britain hopes that other allies will also snub the sporting event . Tougher Sanctions: Theresa May also signaled that Russian oligarchs wanting to come into the UK and live the high life in London will face tough new checks and sanctions. The Government will now back amendments to bring in a Magnitsky Law into the UK - which imposes sanctions on Russians found to be linked to corruption or human rights abuses. Private plane checks While checks on Russian nationals coming to the UK will be stepped up. This will include increased checks on private flights and extra customs checks. The UK will also freeze Russian state assets. Cyber warfare? Mrs May suggested there will be covert action that would not be announced - an apparent hint at cyber attacks. But this is unlikely to ever be confirmed by the Government officially. Advertisement

'The Prime Minister and the President reiterated their condemnation of the use of all chemical weapons and said they would continue to cooperate closely in this area.

'The Prime Minister thanked the President for his ongoing support, including at Nato, the United Nations Security Council and in the OPCW, and they agreed to remain in close contact as the situation developed and in the run up to the March European Council meeting where this would be discussed.'

As Mrs May visited Salisbury today, the military cordoned off part of another village 12 miles away from the city.

The armed forces and emergency services swooped on Alderholt this morning, closing off a road in the area where Wiltshire Police Detective Sergeant Nick Bailey - who was taken to hospital following the nerve agent attack - is believed to live.

Dorset and Wiltshire Fire and Rescue Service said the activity is related to the Salisbury investigation, adding that it was 'on standby to support our colleagues'.

Two large Army low loaders and a crane escorted by police arrived in the village, after residents were told by officers last night that the road would be closed today.

France initially condemned the nerve agent attack on Sergei Skripal and his daughter on Tuesday and expressed solidarity with Britain.

But French government spokesman Benjamin Griveaux yesterday said it was too early for Paris to decide whether action should be taken against Russia.

Shortly after Mrs May said that she was expelling Russian diplomats and suspending bilateral talks, Mr Griveaux told a news conference: 'We don't do fantasy politics.

'Once the elements are proven, then the time will come for decisions to be made.'

While he called the attack a 'very serious act' on a strategic ally, he said that France was waiting for 'definitive conclusions' and evidence that the 'facts were completely true' before taking a position.

Foreign Secretary Boris Johnson admitted there had been different tones coming out of the French government, but said Mr Macron had been solidly behind the UK.

'They issued a joint statement yesterday condemning the attack on UK soil and the PM is speaking to President Macron again today,' he said.

Mr Johnson said the evidence of Russian guilt was 'overwhelming' because only Moscow had access to the poison used and a motive for harming Sergei Skripal.

'There is something in the kind of smug, sarcastic response that we're heard from the Russians that to me betokens their fundamental guilt,' he told the BBC.

'They want to simultaneously deny it and yet at the same time to glory in it.'

Writing in the Washington Post, Mr Johnson said: 'All responsible nations share an obligation to take a principled stance against this behaviour.

'The countermeasures announced by the Prime Minister are not solely about the attack in Salisbury.

'Britain is striving to uphold the rules on which the safety of every country depends. I hope and believe that our friends will stand alongside us.'

Mr Johnson said the attack was a way for Mr Putin to send a message to opponents of his regime that: 'You do that, you are going to die'.

Mr Macron has been on a charm offensive with Russia since becoming president.

He has emphasised private dialogue with Mr Putin, while pushing for a restoration of business and cultural ties despite existing European Union sanctions on Moscow.

Mrs May was today shown the area in Salisbury near where the nerve gas was deployed

Forensic investigators were still hard at work in Salisbury this week following the attack