Vladimir Putin says he wants an inquiry into the Salisbury nerve agent attack, citing a Sky News interview with the boss of Porton Down.

The Russian President also says Moscow would demand to be part of such an investigation.

Russia has called an extraordinary meeting of the Organisation for the Prohibition of Chemical Weapons (OPCW) in the Hague on Wednesday where it will air its complaints about the allegations made against it.

Gary Aitkenhead, chief executive of the Defence Science and Technology Laboratory (DSTL) at Porton Down, told Sky News they had not been able to establish where the novichok nerve agent used to poison Sergei and Yulia Skripal was made.

:: Condition of spy's daughter Yulia Skripal 'improving rapidly'


'Porton Down said it was Russia'

Speaking in Ankara after talks with Turkish President Recep Tayyip Erdogan, Mr Putin claimed novichok could be made in 20 nations.

Given the lack of precise information about the nerve agent's origin, he lamented "the speed at which the anti-Russian campaign has been launched", adding that it "causes bewilderment".

Russia has vehemently denied accusations from Britain that it was behind the poisoning.

:: Salisbury poisoning: Russia issues list of 14 questions for UK

Image: Sergei Skripal's house in Salisbury has been boarded up

Russia's embassy in the UK said it "understood from the very start" that Whitehall statements on the nerve agent having been produced in Russia were "a bluff".

Porton Down fails to tie Salisbury poison to Russia: UK Government loses key piece of its “intelligence picture” – and the rest are kept secret even from Britain’s allies. Read https://t.co/R06NrP6i9h pic.twitter.com/HZYiWiFxQA — Russian Embassy, UK (@RussianEmbassy) April 3, 2018

"Now this has been confirmed by the head of the secret lab," it said.

"This only proves that all political declarations on the Russian origin of the crime are nothing but assumptions not stemming from objective facts or the course of the investigation."

The embassy claimed that novichok may be present in the UK: "We have also noted that, like in his earlier interview, Mr Aitkenhead is not denying that the lab had developed or keeps stocks of the agent they call 'novichok', although, of course, he would not admit it."

Image: The Ministry of Defence's Porton Down research centre

Mr Aitkenhead told Sky News that establishing the nerve agent's origin required "other inputs", some of them intelligence-based, that the Government has access to.

It was "not our job to say where it was manufactured", he added.

Nevertheless, he said novichok required "extremely sophisticated methods to create, something only in the capabilities of a state actor".

There is no known antidote to novichok, he said.