My friend, why do you even bother to try to answer to them? They do not care about the facts, they were told on their "free" television - "Evil Putin ran around Britain at night and poisoned the good people of Britain with poison that he invented personally and the formula of which no one else in the world knew, more over - Americans and British did not know it, because they never worked in Uzbekistan in the institute in which it was invented and tested".
Putin is a killer! Whoaoa! Let's bomb Russia!! Oh, wait, they can bomb us too... Amm... Then we shall just scream around and cry! Damn Russians - why do they have nukes?!? It is so, so unfair!
For one thing, their propaganda machine is running like a classic fascist entity; extremely noisy, repetitive, deaf to alternative point of views and pleas for fact-checking, and increasingly simplistic to serve the low-educated and uncritical masses, in an effort to guide them into certain belief patterns.
UK does everything except following regular customary procedures that are required should such an incident occurs, beginning with sharing Russia a portion of the sample they claim they found in the system of the old victim.
This is definitely a concerted Western effort and they will have radical Islamic/Sunni countries supporting them at the UN because they hate Russia because of Syria (and they have always sided with the West in their holy war against communism).
It appears that the entire Western information apparatus is being mobilized to this end.
Yet, as you say, this is not the 90s, and Russia is not Iraq. What will it all come down to then? I guess they will seek to weaken Russia without openly fighting it. But I do not know how would they be able to weaken Russia's nuclear warheads and delivery platforms. As it seems, they are in fact getting more capable.
Another target (perhaps a main target) will likely be Russia's information dissemination channels. For Russia has been extremely successful in discrediting Western propaganda, playing the Western game in their home turf against them, and influencing global discourse.
This is a serious warning sign to other rising/non-Western/non-compliant strong powers. Western hysteria will get more savage before it ebbs or destroys itself from within.
All this over a mere former spy issue between the U. K and Russia. This is kinda weird and surprising.
