Dave,
if they were certain it would move from being very likely to being absolutely sure

May today in Parliament, "We are quite clear that Russia is responsible for this act."
No politician present expressed dissent, including Corbyn.

EU countries plus USA and Canada have expelled diplomats. That is never done on mere suspicion.

PFR,
'alls' a bit dogmaticaly total innit Keith...???

Yes, and I am right about it.

Nice try!

I linked to the procedure and I have had training, though more than 10 years ago.

. Also for any airborne pathogen or gas

It was not.

The area cordoned off had differing levels of protection inside.

Yes. The yellow suits are required for the hot zone, and are removed in the warm zone where less protection is required.