A London hotel room, counterfeit perfume and 11,000 hours of CCTV footage: How Russian novichok suspects were found

Police investigation shares similarities with discovery of polonium trail left by those accused of murdering Alexander Litvinenko

One of the keys to identifying the two men allegedly responsible for the Salisbury poisoning lay in the discovery of traces of novichok in their hotel room in London, similar evidence to the polonium trail left by the two men accused of murdering Alexander Litvinenko 12 years ago.

The security agencies concluded fairly early in their investigation that the attack on former Russian intelligence officer Sergei Skripal and his daughter Yulia was carried out by people who had arrived at the country from abroad rather than those based here.

The checking of names of airline passengers focused on those who had come from Russia for unusually short visits and two of the names which came up were those of Alexander Petrov and Ruslan Borishov.

They had flown in from Moscow to London’s Gatwick airport on an Aeroflot flight on 2 March, two days before the attack, and flew out of Heathrow airport on the evening after it took place.

Tracing their movement in the UK, checking through 11,000 hours of CCTV footage, led to the two star City Stay Hotel in east London.

It was established that they had carried out a reconnaissance trip to Salisbury on Saturday before returning to the city on Sunday and putting the novichok, carried in a bottle of counterfeit Nina Ricci perfume, on the front door of the Skripals’ home.

The pair then flew back to Moscow on an Aeroflot flight at 10.30 in the evening.

Unlike Andrei Lugovoi and Dmitry Kovtun, the suspects in the Litvinenko poisoning, the Salisbury attackers were almost certainly using false names although the Russian passports they travelled on were genuine.

Despite reports to the contrary, there have been no plans to seek extradition of the suspects from Russia because there is no extradition treaty between the country and the UK.

The chances of the Kremlin sending the two men to face trial here is considered to be remote, just as it was never likely that Lugovoi and Kovtun would be delivered over Mr Litvinenko’s murder.

A European arrest warrant has, however, been obtained, which means that the two men could be arrested in any country where it is valid and extradited to the UK.

The British government accused the Russian government of culpability for the attack soon after it took place and evidence that has emerged since then has only reinforced that view, a very senior intelligence official told The Independent last week.

Investigators believe the attack was carried out by GRU, the Russian military intelligence service for which Mr Skripal had worked when he was recruited by MI6. Security sources maintain that even if the poisoning was carried out as “private action”, possibly in revenge for colleagues betrayed by Mr Skripal, it could not have been carried out without the knowledge of senior Kremlin figures.

The Russian government has continued to deny any involvement in the Salisbury attack, as was to be expected.

Foreign ministry spokeswoman Maria Zakharova declared that the names of the suspects and the photos of them “say nothing to us”. She urged Britain to “refrain from public accusations” and work with Russian law enforcement authorities to investigate the attack.

Twenty-four hours before details about the suspects were released by Scotland Yard, Russia accused the British authorities of ignoring repeated offers of a joint inquiry.

It complained that “the United Kingdom continues to blatantly violate Russia’s lawful right to communicate with its citizens in accordance with Article 36 of the 1963 Vienna Convention on Consular Relations and Article 36 of the 1965 bilateral Consular Convention. Moreover, the de facto deprivation of liberty of the Skripals is highly questionable from the point of view of observance of their rights confirmed in the 1948 Universal Declaration of Human Rights and the 1950 Convention for the Protection of Human Rights and Fundamental Freedoms.”