Sir Andrew Wood, a former British ambassador to Russia has said that it is not possible to know whether President Vladimir Putin “personally ordered, rather than gave a general authorisation” but “there is no doubt that he is overall responsible”.
Sir Andrew Wood told talkRADIO’s Julia Hartley-Brewer: “There is no way that you could tell whether he personally ordered rather than gave a general authorisation to this operation.
“He would not have been consulted about the details.”
Police have said there is sufficient evidence to charge Alexander Petrov and Ruslan Boshirov with conspiring to murder Sergei Skripal and attempting to murder the ex-Russian spy, his daughter Yulia and Wiltshire Police detective sergeant Nick Bailey.
Prosecutors will not be applying to Russia for the extradition of the two men, but a European Arrest Warrant has been obtained.
Detectives believe the front door of Mr Skripal's Salisbury home was contaminated with the military-grade substance on Sunday March 4.
They said CCTV shows the two suspects in the vicinity of the property on that date.
Hours later, the men left the UK on a flight from Heathrow to Moscow - two days after they had arrived at Gatwick.
‘There is no doubt’
Sir Andrew Wood added: “He has given blanket authorisation and there is no doubt at all that he is personally overall responsible.
“We will never prove, and I think it would be rather surprising if, he had given a direct order in this particular case.”
Britain called a meeting at the UN Security Council on Wednesday, of which Russia is permanent member, to update members on the investigations into the Novichok attacks.
Russia claimed that the UK was trying to unleash “disgusting anti-Russian hysteria” during talks at the United Nations.
Diplomat Vasily Nebenzya told the UN security council: "I'm not going to go through the list of this whole unfounded and mendacious cocktail of facts.
"London needs this story for just one purpose - to unleash a disgusting anti-Russian hysteria and to involve other countries in this hysteria."