The UK should be basing its actions on the need to put a stop to the overall Russian policy of assassinating people abroad. For this policy of officially sanctioned assassinations is set in Russian law and advocated in public statements by the Russian leadership, including those made by President Vladimir Putin.
https://rusi.org/commentary/uk-and-russia-what-be-done
In his fourth term, will he push Russia to become an economic power?
https://www.svoboda.org/a/29109319.html
https://www.levada.ru/2018/03/20/poslanie-federalnomu-sobraniyu/
https://ru.krymr.com/a/29111204.html
http://www.kasparov.ru/material.php?id=5AB1578A9115F
https://www.kommersant.ru/doc/3578068
https://www.kommersant.ru/doc/3578493
https://www.kommersant.ru/doc/3578381