It is hard to trust the word of either government.
Britain has a government that pursues an extreme agenda saying it is the “will of the people” when that is clearly untrue. The accusation against Russia, in this case, does appear logical but the photos of two men
Putin’s statement that they are civilians is not very well supported by the two men’s story, which sounds rather silly, especially their statement that men would not carry women’s perfume on a plane without arousing suspicion. Who else would target enemies of the Russian state?
The UK has already spent millions on this. Due process is expensive. Russia has lost far more due to sanctions.
You got to ask, who benefits? Who are enemies of both states?
See also: https://www.theguardian.com/commentisfree/2018/sep/13/skripals-russia-putin-salisbury-poisoning-suspects-interview