The British government is poised to submit an extradition request to Moscow for two Russians suspected of carrying out the Salisbury nerve agent attack that left one person dead and four injured, according to Whitehall and security sources.



The move comes after months of painstaking investigation by hundreds of officers from the police and the intelligence agencies. They have pieced together the movements of the two Russians, from their entry into the UK through to their departure.



The Crown Prosecution Service, which prepared the extradition request, has completed the process and is ready to file, the sources said.

The request will reignite the simmering diplomatic row with Russia, which is certain to reject it, prompting another round of tit-for-tat diplomatic expulsions.

Relations between the UK and Russia sank to their lowest point since the end of the cold war after the nerve agent attack on Sergei Skripal, a former colonel in Russian military intelligence, and his daughter, Yulia, in Salisbury in March. They were found unconscious on a bench in a shopping centre after being exposed to novichok.

UK intelligence chiefs have specifically blamed Russia for the attack.

Charlie Rowley and Dawn Sturgess were subsequently treated for exposure to the nerve agent. Rowley recovered but Sturgess died.



DS Nick Bailey from Wiltshire police was also taken to hospital after being exposed to the nerve agent.

The Kremlin has denied any responsibility and waged a furious campaign of counter-accusation. It has suggested the UK is holding the Skripals against their will and denying them Russian consular assistance.

People in protective suits collect an item and photograph its location in Salisbury. Photograph: Hannah Mckay/Reuters

Any British government request is likely to meet with a scornful response from Moscow. Vladimir Putin, the Russian president, has previously complained of the UK’s refusal to extradite high-profile critics, including the late oligarch Boris Berezovsky.



The decision to press for extradition follows intense debate within Whitehall, divided between those who want to ratchet up the response to Russia and those who see the request as a futile political gesture.

Putin rejected a similar extradition request in 2007 for two Russians suspected of being behind the 2006 assassination with polonium of the former FSB officer Alexander Litvinenko in London.

A Whitehall source said: “The CPS has been asked to prepare extradition requests and we understand they are ready to go. This is Litvinenko all over again. It’s almost a rerun of the situation. The police have managed to identify the people coming over and going back again.”

Police and intelligence officers believe the novichok used to attack the Skripals on 4 March was applied from a perfume bottle sprayed or smeared on to their front doorknob. Both of them recovered.

Police are working on the assumption that the bottle was dropped somewhere in the city, where it was later picked up by Rowley, who gave it to Sturgess. The pair were taken to hospital on 30 June.

Sturgess received a much higher dose than the other four after apparently smearing the substance on her wrists, having sprayed it from the bottle. Rowley’s recovery was helped, according to a source, by one of the first responders being familiar with the nerve agent, having been involved in helping the Skripals.

The Porton Down military defence laboratory near Salisbury has examined the novichok found on the Skripals’ doorknob and the perfume bottle, but police have not yet said whether they are from the same batch.



The Organisation for the Prohibition of Chemical Weapons, based in The Hague, which helped with the investigation into the Skripals, sent a team to the UK in July to collect samples from the incident involving Sturgess and Rowley. They were sent to two OPCW laboratories.

Yulia and Sergei Skripal were poisoned on 4 March in Salisbury city centre. They have since been discharged from hospital. Photograph: Handout

An OPCW spokesperson declined to confirm on Monday whether the novichok was from the same batch. “The technical assistance is ongoing,” they said.

A source said establishing that the nerve agent is from the same batch is more complicated and time-consuming than is generally assumed.

The UK national security adviser, Sir Mark Sedwill, has been among Whitehall officials pressing hardest for a more robust response towards Russia. He used a letter in April to the Nato secretary general, Jens Stoltenberg, to disclose previously classified intelligence material claiming Russia had tested using nerve agents on door handles and targeted the emails of both Skripals since 2013.



Sedwill, who is standing in for the UK’s most senior civil servant, Sir Jeremy Heywood, who is on a leave of absence, was described by one source as being “very bullish”.

“He is encouraging taking a stand. He has been very aggressive on Russia since the Skripal attack,” they said.

Giving evidence to a select committee in May, Sedwill said police had not yet identified those responsible.

A security source said the attack on the Skripals was ordered by the GRU, Russia’s military intelligence service, rather than the FSB, which is roughly equivalent to MI5. Skripal, a former GRU colonel, was turned by the UK overseas intelligence agency, MI6. The GRU has a history of conducting crude revenge attacks on those who have betrayed it.



The Russian government insists it will not extradite any Russian citizen, although it has occasionally made exceptions.



Litvinenko fled from Moscow in 2000 and became a leading Putin critic in exile in Britain. The journalist and writer was employed by MI6, reportedly as an expert on Russian organised crime.

In May 2007, the Foreign Office put in a formal request for the extradition of Andrei Lugovoi, who was the main suspect and is now a Russian MP. Moscow refused and the UK responded by expelling four Russian diplomats.

Another extradition request in connection with Litvinenko was made in 2012 for Dmitry Kovtun, but it was also blocked. In 2016, a public inquiry concluded that Lugovoi and Kovtun killed Litvinenko. Both deny involvement.

Elena Tsirlina, a lawyer for Litvinenko’s widow, Marina, said Russia’s response to the extradition request would be an expression of outrage. “They will move to protect the suspects and cite article 61 of the Russian constitution, which prevents Russian citizens from being extradited to another country,” she said.

Attempts to extradite Lugovoi and Kovtun had clearly failed, with both suspects “beyond the UK’s grasp”, Tsirlina said. The government should therefore hold a public inquiry into the Salisbury nerve agent attacks.

“I strongly believe a public inquiry should be convened, for the sake of transparency and Britain’s international standing. This would be an opportunity to hear all of the police evidence in the Skripal case and to examine it openly,” she said.

