The location of manufacture "can be established through a number of different input sources which the Government has access to", he said, adding: "From our perspective, scientific evidence is only one of those sources, and it requires a number of other things to verify that".
Gary Aitkenhead Chief Executive of the Porton Down defence laboratory handling the case investigation said that analysts had identified it (nerve agent) as military-grade Novichok but they had not proved that it was made in Russian Federation as per news outlet France 24.
The British government insisted that several pieces of information contributed to its conclusion that the Russian government was responsible for the nerve agent attack, including intelligence that Russia had produced Novichok within the last decade and had investigated ways of delivering nerve agents for assassinations.
"It is our job to provide the scientific evidence of what this particular nerve agent is, we identified that it is from this particular family and that it is a military grade, but it is not our job to say where it was manufactured", Aitkenhead said.
Aitkenhead said Tuesday that the attack with a highly toxic Novichok nerve agent was "probably only within the capabilities of a state actor".
Asked to clarify, he said: "A real war, worse than a cold war is a real war, it will be the last war in the history of mankind".
Fox proposes selling Sky News to Disney
A surprise offer for Sky from Comcast, the U.S. cable group, at a premium to the Fox offer has further complicated the picture. Indeed, popular British news outlets owned by the Murdoch family include newspapers the Sun , the Time and the Sunday Times.
British officials have previously rejected similar Russian allegations.
Meanwhile, Russian president Vladimir Putin on Tuesday expressed hope that a meeting of the world's chemical weapons watchdog would put a "full stop" to the issue.
At Russia's request, the Organization for the Prohibition of Chemical Weapons plans to hold an emergency meeting on the case Wednesday at its headquarters in The Hague.
The meeting on April 4 - to be held behind closed doors - was called by Russian Federation to "address the situation around allegations of non-compliance" with the chemical weapons convention made by the United Kingdom against Moscow.
London has accused Russian Federation of using the Novichok nerve agent, developed in the latter days of the Soviet Union. We expelled diplomats. You further expel, what is the next step?
SNCF strike disrupts travel in France
What remains unclear is whether Macron might offer further concessions to get the unions to back down before the strikes bite. SNCF workers fear they could lose job-for-life guarantees, automatic annual pay rises and a generous early retirement policy.
The 'secret bank account' was disclosed by Sergei's niece Viktoria Skripal, 45, who aims this week to travel to meet Yulia in hospital in Salisbury.
Skripal, 66, a former Russian intelligence agent convicted of spying for Britain, remains in critical condition.
Russian Deputy Foreign Minister Alexander Grushko called the poisoning a "provocation arranged by Britain" in order to justify high military spending because "they need a major enemy".
A RETIRED Russian general has warned that the fallout from the Salisbury attack could trigger "the last war in the history of mankind".
A senior Lithuanian official who asked not to be named said they would ask the U.S. to send Patriot long-range anti-aircraft missiles more frequently for war games.
USA keen to work with Egypt's re-elected President Abdel Fattah al-Sisi
Turnout was 41 percent, despite efforts to get as many Egyptians as possible to polling stations during last week's vote. He said 92.73% of the votes were valid from the roughly 24 million cast, while nearly two million ballots were spoiled.
He said that if Britain does not show evidence to back up its allegation, "there are ample grounds to assume that we are dealing with a grand scale provocation organized in London aimed to discredit Russian Federation".