"No other explanation other than it was Russia who carried it out given the nature of the nerve agent which OPCW yesterday (Thursday) has confirmed that it was a Soviet era nerve agent of the very highest purity," Asquith said during a media briefing here.
"There can be no other entity that could have made it.
"So, OPCW has confirmed what we have been saying and the Russians have been contesting," he said.
The chemical attack was made on former Russian spy Sergei Skripal, 66, and his daughter, Yulia, 33, in the British city of Salisbury on March 4.
The OPCW, which conducted its probe at the request of the British government, analysed samples collected by British authorities from Skripal, Yulia and a police officer exposed to the nerve agent and concluded the chemical was "of high purity".
Its report came after the Western countries expelled over 100 Russian diplomats from their countries in response to the poisoning, straining relations between Russia and the West.
Western leaders said they agreed with Britain's assessment that it was highly likely Russia was responsible for the attack. The Kremlin has consistently denied any involvement.
The report puts beyond doubt that it was highly likely Russia carried out the attack, people close to the investigation said, adding that the nerve agent could only be concocted in a very sophisticated laboratory by highly capable chemists who were familiar with the agent.
The deadliness of the agent depended on the dose and how it was inhaled. The OPCW was not tasked to identify where the nerve agent came from. The purpose was only to confirm the identification of the nerve agent used.
The full report by the OPCW, which was classified, mentioned the chemical structure of Novichok but did not use the name. The Novichok class of nerve agents was developed in Russia and its existence was first revealed in the early 1990s by a dissident scientist.
"In our view, there are really important questions the Russians have to answer," Asquith said.
"From our perspective, it is really an important attack to take note of and not to allow to pass by without it being pinpointed.
"As we say, there are many questions the Russians have to answer. They have not answered. All they have done so far is to try and deflect the questions, to obstruct the investigation."
Asquith said that this was exactly the same that Russia seemed to be engaged in the case of a reported attack in the use of nerve agent in Syria.
The suspected attack, denied by Syrian President Bashar al-Assad's government, was carried out last week, reportedly killing over 70 people.
India on Thursday said that it is waiting for the result of the investigation into the attack on Skripal and his daughter.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
