lavrov
It better be something good!
What is good for the goose is good for the gander. At least Russia seems to think so. There may not be conclusive evidence Britain poisoned Sergei Skripal and his visiting daughter Yulia. But then neither is there evidence Moscow did it and that did not prevent London from demanding Russia proves its innocent (in 24 hours). Moreover the British are keeping Russians away from evidence, not the other way around.

So why wouldn't Russia now demand Britain instead proves its own innocence? Well, Lavrov's Ministry of External Affairs can't think of a reason why not.
Russia has demanded that London provide proof that British spies did not carry out the poisoning of former double agent Sergei Skripal.

The Russian Foreign Ministry said in a statement that their analysis of the assassination attempt has them to believe in 'a possible involvement in it of the British intelligence services'.

The Ministry says that in the absence of proof of British innocence, Moscow will regard the incident as an attempt on the lives of Russian citizens on foreign soil.

'An analysis of all the circumstances ... leads us to think of the possible involvement in it (the poisoning) of the British intelligence services,' the foreign ministry said in a statement.

'If convincing evidence to the contrary is not presented to the Russian side we will consider that we are dealing with an attempt on the lives of our citizens as a result of a massive political provocation.'
Excellent! 'Do what you demand of us and prove your innocence to us, or we will regard it was a state-sponsored attempt at murder of our citizens.'

Lavrov has truly outdone himself here. And yet all he has done is responded in kind. So simple and yet so brilliant.