Russian Foreign Minister Sergey Lavrov has dismissed Britain's claim of Russia's involvement in Skripal's poisoning as "nonsense". He has also said that Britain has refused Russia's offer of cooperation to solve the case, and has also refused what he called Russia's "legal request" for samples of the chemical used to attack Skripal so that Russia can carry out its own tests.
Latest reports also say that the Russians have summoned the British ambassador to the Russian Foreign Ministry.
That the Russians have rejected yesterday's British ultimatum will surprise no-one. I would however point out how completely bizarre this whole situation has become.
The Russians are being asked to provide proof of their innocence - already a bizarre request - whilst being denied the evidence which supposedly 'proves' their guilt.
The British have referred to the Organisation for the Prohibition of Chemical Weapons ("OPCW") as the agency to which the Russians are supposed to provide 'proof' of their innocence.
However whenever there have been chemical attacks in Syria the British and others have demanded that this same organisation should be the one to carry out the investigations into those attacks.
Those investigations, whenever they have happened, have taken months.
The British however in this case insist on carrying out the entire investigation by themselves despite the supposed international dimension of the case, refuse to share their evidence with the party they are accusing, claim to have come to a view within days, and are using the OPCW as nothing more than a post box.
The British do say that they have consulted 'international experts' who have verified the identity of the chemical that was used.
However we have no word of who these experts are or what were the criteria used for their selection, and their reports have not been published.
All this of course all relates solely to the identity of the chemical that was used in the attack. Important though that information is, it is not and cannot be the entirety of the evidence used to make a finding of guilt or innocence in a case like this.
Perhaps the British have other evidence which they believe confirms Russia's guilt but which is too classified to make public.
However in that case this evidence cannot be used to make a finding of guilt or innocence since the party accused - in this case Russia - is being denied access to this evidence and is therefore denied a chance to refute it.
For what it's worth my opinion based on what Theresa May said to Parliament yesterday is that the British have no such further evidence. If they did I would have expected her to at least to hint at it. On the contrary the fact that Theresa May even raised the possibility that the attack might have been the work of a rogue element shows how little about the attack the British actually know.
It is precisely because the British have no conclusive evidence which proves Russian guilt - secret or otherwise - that they are trying to create the appearance of such evidence by sending to the Russians an ultimatum which reverses the burden of proof.
There has been much discussion in the British media about how yesterday Theresa May put Vladimir Putin on the spot.
On the contrary my opinion is that the person who Theresa May put on the spot yesterday - and not for the first time since she became Prime Minister - is herself.
Having cranked up the crisis to extraordinary levels - with massive deployments of troops and anti-terrorist police to investigate the incident, and with contradictory and alarming messages given to the people of Salisbury - and having given Russia an ultimatum yesterday - and done so moreover in the most public way possible - Theresa May will struggle to live up to expectations she has herself created.
Already talk of England pulling out of the World Cup in Russia looks to have been abandoned - it would be deeply unpopular with the English public - and wild talk of breaking off diplomatic relations with Russia and launching cyber attacks against Russia are utterly self-defeating and look farfetched. I sense no enthusiasm in Europe for further significant sanctions against Russia, and talk of an appeal to NATO under Article 5 is already being discounted.
Comment: Skripal Likely Poisoned by British Intelligence in Effort to Smear and Silence Russian World View
Yet if Theresa May fails to live up to the expectations she has herself created she risks being humiliated and looking weak.
There has been much talk in Britain of how Theresa May has been pressured into taking this extreme stand by hardliners within the British government.
If so then it is yet more evidence - if any more were needed - that Britain has a weak Prime Minister who is easily pressured into taking steps which are counterproductive and contrary to Britain's own interests.
By contrast Labour leader Jeremy Corbyn in Parliament yesterday - by refusing to join in the finger pointing against Russia, by speaking of the need for a continued dialogue with Russia, and by calling for the investigation into the Skripal attack to be allowed to take its course - cut a lonely figure of good sense.
The fact that he did so in the face of what he must have known in advance would be universal outrage and condemnation from across Britain's political and media establishment shows that he possesses reserves of strength and self-confidence which Theresa May utterly lacks.