Whilst some controllers may be 'uneasy' about the final destination of any 'hazardous cargo', I would hope all would want to know the cargo was hazardous so their actions could be 'informed' in an amergency in UK airspace.
Otherwise, why do we have statutory notification procedures?
I am sure the Fire Service (and a few others) would like a 'heads up' on the fact that several kilotonnes of bunker buster bombs was heading earthwards in a civilian-registered cargo plane. (also some could have depleted uranium tips!)