Two Russian intelligence officers are suspected to have carried out the attempted murder of Russian ex-spy Sergei Skripal, which was nearly certainly approved "at a senior level" of the Russian state, British prime minister Theresa May revealed Wednesday.
Mr Fleming said the intelligence community had supported police in a "painstaking" and "highly complex" investigation into what happened after the poisoning of former Russian spy Sergei Skripal and his daughter Yulia in Salisbury on 4 March.
The prime minister did, however, reveal the two suspects who flew into Britain with the novichok were officers in the GRU, Russian military intelligence, as police laid out a compelling trail showing how the suspects travelled from Moscow to London and then on to Salisbury, featuring numerous CCTV images and supporting detail.
The Canadian government has backed British claims that Vladimir Putin's government "almost certainly" approved a poison attack against a former Russian spy and his daughter in the United Kingdom earlier this year.
Relations between Canada and Russian Federation have not been spared, with the two countries involved in various wars of words and tit-for-tat diplomatic expulsions - including one round in March that was in direct response to the Salisbury attack.
"We will not be applying to Russia for the extradition of these men as the Russian constitution does not permit extradition of its own nationals", said Sue Hemming, director of Legal Services at the Crown Prosecution Service.
"We now have sufficient evidence to bring charges in relation to the attack on Sergei and Yulia Skripal in Salisbury and domestic and European arrest warrants have been issued for the two suspects".
"We know that Novichok was applied to the Skripals' front door in an area that is accessible to the public, which also endangered the lives of members of the public and emergency service responders", Basu said. Therefore, an upsurge in her wants to add to the list of Russian names on a European Union travel ban, and penalties for misuse of chemical weapons can be quite easily seen.
Sergei Skripal - a former Russian agent who had been convicted in his homeland of spying for Britain - and his daughter were found collapsed on a bench in the cathedral city of Salisbury, 140 kilometres southwest of London. They were both since discharged from the Salisbury District Hospital.
The Skripals and Bailey both recovered, but on June 30, a British couple fell ill from the same type of nerve agent in the nearby town of Amesbury.
Ms. Zakharova called on Britain to cooperate with Russian law enforcement agencies on the investigation.
Security cameras filmed the suspects near Skripal's house, and traces of Novichok were found in their London hotel room.
Mr Basu would not say whether police believe the suspects worked for Russian security services but, he said, "this was a sophisticated attack across borders". "Two swabs showed contamination of Novichok of levels below that which would cause concern for public health", Basu said. They flew out on March 4, hours after the Skripals were found unconscious.
Her partner, Charlie Rowley, 48, was also treated in the same Salisbury hospital and later released. He was hospitalized and his girlfriend Dawn Sturgess died after being exposed to the contents.
The Organisation for the Prohibition of Chemical Weapons confirmed Tuesday that Rowley and Sturgess were also exposed to Novichok.
Basu said they ha no doubt the two events were connected and they were liaising with prosecutors about bringing charges connected to the poisoning of Sturgess and Rowley.