Updated 21:05

Russia has lost a vote at the international chemical weapons watchdog calling for a joint investigation into the Salisbury spy poisoning.

Officials from the Executive Council of the Organisation for the Prohibition of Chemical Weapons (OPCW) met for an extraordinary sitting today following a request from Russia.

Six countries supported Moscow’s call for a joint investigation into the attack - but 15 voted against them while 17 abstained.

The British government has accused Russia of being responsible for the attack on former Russian spy Sergei Skripal and his daughter Yulia - a claim Moscow has vehemently denied.

Russian diplomats were expelled from Ireland, the UK, US, Canada, Australia and countries across Europe after the British Prime Minister Theresa May said there was “no alternative conclusion other than that the Russian state was culpable” for the attack.

British officials have described the request for a joint investigation as "perverse."

Russian President Vladimir Putin made the demand after the head of the UKs chemical research facility admitted researchers had been unable to determine where the nerve agent used in the attack was made.

Russian agent

Gary Aitkenhead, chief executive of the UK Defence Science and Technology Laboratory (DSTL) at Porton Down in Wiltshire, said their analysis was only able to confirm the substance involved was novichok – a military-grade nerve agent developed by Russia from the 1970s onward.

He added: “We have not verified the precise source but we provided the scientific information to the Government who have then used a number of other sources to piece together the conclusions that they have come to."

He suggested the chemical could only have been manufactured by a 'state actor', and dismissed any suggestion of British responsibility - insisting "there is no way anything like that could have come from us or left the four walls of our facility".

Calls for investigation

The latest developments prompted calls for an inquiry from Russian President Vladimir Putin, who claimed the chemical could have been manufactured in 20 countries.

Speaking in Ankara, he said: "We want to be allowed to participate in the investigation and we are counting on receiving the respective materials, since it involves Russian citizens."

The Russian leader also lamented "the speed at which the anti-Russian campaign has been launched," adding that it "causes bewilderment".

The British government's claims of Russian responsibility in the Salisbury attack have prompted a strong reaction from their allies - with more than two dozen countries, including Ireland, having expelled Russian diplomats in solidarity with the UK.

Russia has responded with tit-for-tat expulsions of western diplomats.

While Sergei Skripal remains in a critical condition, doctors last week said his daughter's condition has improved rapidly - with British media reporting she is conscious and talking.

Chemical weapons investigators from the OPCW have already collected samples in Salisbury, with their test results expected in the coming weeks.

With reporting from Michael Staines ...