UK lab 'hasn't identified' source of nerve agent used on spy

The head of the British military facility analysing the Novichok nerve agent used to poison Russian spy Sergei Skripal and his daughter said today it has "not identified the precise source" of the substance.

Gary Aitkenhead, chief executive of the Porton Down defence laboratory, told Britain's Sky News that analysts had identified it as military-grade Novichok, but they had not proved it was made in Russia.

"We have not identified the precise source, but we have provided the scientific info to government who have then used a number of other sources to piece together the conclusions," he said.

"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."