Firstly, they would’ve been dead. Yulia would’ve been dead in Russia where she lived. And Sergei would’ve been dispatched at a less sensitive time by rather more reliable, less identifiable means, and by rather less comical killers. The killers would not have flown directly from and back to Moscow. They would not have entrusted their egress to the Sunday service of Wiltshire public transport. They would not have smiled up at every CCTV camera they could find.
https://www.rt.com/op-ed/452961-skripal-novichok-poisoning-britain/
