The European Union has demanded that the Russian government hand over for scrutiny all information about the nerve agent that allegedly poisoned a former spy on British soil.

At a meeting in Brussels on Monday the EU’s 28 foreign ministers condemned the “reckless and illegal” poisoning of Sergei and Yulia Skripal and said information about the Novichok nerve agent should be handed over to the Organisation for the Prohibition of Chemical Weapons investigation.

The UK says the Russian-developed nerve agent was responsible for the attempted killings and that all signs point to Vladimir Putin’s government being behind the incident in Salisbury on 4 March this year. Russia says allegations that it carried out the attack are “slanderous, groundless, and difficult to explain”, and has said that any stockpiles of Novichok would have been destroyed in accordance with international treaties.

EU foreign ministers’ joint statement stopped short of directly blaming Russia in the way the UK government has, however, only stating that the “European Union takes extremely seriously the UK Government’s assessment that it is highly likely that the Russian Federation is responsible”.

Foreign ministers were briefed by Boris Johnson on the issue before drawing up the joint statement. European Commission foreign affairs chief Federica Mogherini said arriving at the summit that the EU pledged “full solidarity” with the UK and said there was “extreme concern” about what happened.

“The European Union is shocked at the offensive use of any military-grade nerve agent, of a type developed by Russia, for the first time on European soil in over 70 years,” the joint statement says.

“The use of chemical weapons by anyone under any circumstances is completely unacceptable and constitutes a security threat to us all. Any such use is a clear violation of the Chemical Weapons Convention, a breach of international law and undermines the rules-based international order.

“The EU welcomes the commitment of the UK to work closely with the Organisation for the Prohibition of Chemical Weapons (OPCW) in supporting the investigation into the attack. The Union calls on Russia to address urgently the questions raised by the UK and the international community and to provide immediate, full and complete disclosure of its Novichok programme to the OPCW.

“The European Union expresses its unqualified solidarity with the UK and its support, including for the UK’s efforts to bring those responsible for this crime to justice. The EU will remain closely focussed on this issue and its implications.”

Arriving at the summit Mr Johnson the Foreign Secretary warned the Russian government that it is “not fooling anyone” with its “increasingly absurd” denials of culpability for use of a nerve agent on British soil.

He added that he had been “heartened” by support for the UK and that Britain was acting “in punctilious accordance with our obligations under the treaty on chemical weapons” – in contrast, he said, to Russia.

Officials from the Organisation for the Prohibition of Chemical Weapons are arriving in the UK today to take samples of the nerve agent used in the attempted assassination of Sergei Skripal and his daughter Yulia, he confirmed. The British government says the substance is Novichok, a Russian-developed weapon, but Russia has denied have any stockpiles of it.

“The Russian denials grow increasingly absurd. At one time they say they never made Novichok, at another they say they did make Novichok but all the stocks have been destroyed, and then again they say that they made Novichok and all the stocks have been destroyed but some of them have mysteriously escaped to Sweden, the Czech Republic, Slovakia, the United States, or even the United Kingdom,” he told reporters on the summit doorstep.

Boris Johnson addresses reporters in Brussels (AP)

“I think what people can see is that this is a classic Russia strategy of trying to conceal the needle of truth in a haystack of lies and obfuscation. What really strikes me talking to European friends and partners today is that 12 years after the assassination of Alexander Litvinenko in London they’re not fooling anybody anymore.

“There is scarcely a country around the table here in Brussels that has not been affected by some kind of malign of disruptive Russian behaviours. That is why I think the strength and resolve of our European friends is so striking today.”

Spanish foreign minister Alfonso Dastis told reporters as he arrived: “We think now the time is for an extended examination of all the elements involved with the participation of the OPCW. We are definitely going to keep the issue under consideration in the context of the EU, we’ll see.”

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

EU foreign affairs chief Ms Mogherini said: “We have a particularly intense agenda today with the ministers. First and foremost we’ll hear from Boris Johnson for a debrief on Salisbury.