...The substance used on Sergei Skripal was an agent called BZ, according to Swiss state Spiez lab, the Russian foreign minister said. The toxin was never produced in Russia, but was in service in the US, UK, and other NATO states.
Sergei Skripal, a former Russian double agent, and his daughter Yulia were poisoned with an incapacitating toxin known as 3-Quinuclidinyl benzilate or BZ, Russian Foreign Minister Sergey Lavrov said, citing the results of the examination conducted by a Swiss chemical lab that worked with the samples that London handed over to the Organisation for the Prohibition of the Chemical Weapons (OPCW)....RT quoted at Vox Pop
I suppose that a Russki agent could have gone down to the apothecary and purchased some BZ, of course.
Otherwise, as Vox asks: Why would the Brits lie about this?