UK security minister explains rejection of joint inquiry with Russia

A joint investigation with Russia would be "like asking Al Capone to verify his own tax return", according to Security Minister Ben Wallace.

The UK rejected Russia's proposal over the Salisbury nerve agent attack, describing the offer as "perverse".

It comes after the head of the Porton Down laboratory said he had not established the source of the Novichok used to poison Sergei and Yulia Skripal.