I've watched enough spy movies to posit this spin on the story...

Father and daughter used their old network of contacts to steal and smuggle some of the nerve stuff in for Porton Down...
Then unfortunately.. big oops... accidental spillage while waiting in a pub to hand the parcel over....???????????

MI6 - "Oh dear.. what do we do, we've been caught with our trousers down..
I know lets blame Russia and hope no one asks too many awkward questions...????"