Mark Sedwill said in a letter to NATO Secretary General Jens Stoltenberg on Friday that email accounts of Yulia had been targeted in 2013 by cyber specialists from Russia's GRU military intelligence service.
The Skripals were found slumped on a bench in the English city of Salisbury on March 4.
The incident has led to a diplomatic crisis between Moscow and the West as Moscow denies any involvement and accuses Britain of inventing a "fake story".
"The results of analysis by OPCW-designated laboratories of environmental and biomedical samples confirm the findings of the United Kingdom relating to the identity of the toxic chemical that was used in Salisbury and severely injured three people", the summary said.
The analyses thus confirm that neurotoxic used in attack on Russian ex-spy Sergey Skripal and his daughter was produced in Russia, although in two-page communiqué name of that country does not appear.
Mr Sedwill said Russian Federation further developed some Novichoks after ratifying the convention, and failed to report the activity. "The document only strengthens suspicions that we are dealing with a forcible isolation of the Russian citizen".
'We would like to make sure that the statement really belongs to Yulia, ' the embassy said.More news: Real Madrid v Juventus: Thrills, spills & penalty aches
North Atlantic Treaty Organisation confirmed it had received the letter, with a North Atlantic Treaty Organisation official saying that the allies were "united in condemning the use of a nerve agent in Salisbury and we stand in solidarity with the United Kingdom".
Lavrov also said the Swiss experts had found that the Skripals' samples contained traces of A-234 - one of the nerve agents of the novichok group - "in its original form" and in considerable quantities.
The government of Prime Minister Theresa May expelled 23 Russian diplomats in retaliation and called on ir worldwide allies to follow in ir footsteps.
"We will now work closely with our partners to clarify grotesque use of this weapon and convene OPCW council to discuss next steps", Johnson said Thursday through a statement collected by Reuters.
He said Russian Federation developed some Novichoks even after ratifying the convention.
The nerve agent attack on two people in England "demonstrates how reckless Russian Federation is prepared to be, how little the Kremlin cares for the global rules-based order", one of Britain's intelligence chiefs said Thursday, in an unusually public and scathing commentary on a foreign power. "Within the last decade, Russian Federation has produced and stockpiled small quantities of Novichoks under the same programme", he said.
Russian Federation vehemently denies being behind the attack in Salibury. The embassy posted on Twitter on Tuesday: "We need urgent proof that what is being done to her is done on her own free will".