There's a satirical german article related to this topic: http://www.der-postillon.com/2018/03/putin-salisbury.html

Literally translates to:

Salisbury Poison Attack: British police find Putin's ID card at the crime scene

Imo this perfectly describes what happened. Even if the Russians had a reason to kill Skripal, why the heck would they use a Russian military poison? And I'm pretty sure they wouldn't fail if they really tried.