Section 12 of the Licensing Act 1872 provides an offence for being drunk with a loaded firearm: “Every person who is drunk while in charge on any highway or other public place of any carriage, horse, cattle, or steam engine, or who is drunk when in possession of any loaded firearms,
may be apprehended, and shall be liable to a penalty not exceeding forty shillings, or in the discretion of the court to imprisonment for any term not exceeding one month”.
So, as can be seen, the firearm in question has to be loaded. Obviously the penalties have developed since 1872.
As for evidence of drunkenness, police officers can indeed give evidence of drunkenness and are held in law to be expert witnesses for that purpose. Agree with it or not, cops deal with drunks in their work on a daily basis. As such an expert witness, I have multiple times given such evidence which has been accepted by the court. Of course, like any evidence, expert or otherwise, you can be cross examined and challenged about it and your evidence might or might not be substantiated. Quite often this happens when giving evidence of someone's state of mind by doctors. I recall one officer who, in the witness box giving evidence of drunkenness stating the defendant's eyes were glazed. He was challenged on that when the defence solicitor told him the defendant wore contact lenses. The officer replied he looked "double glazed". His "expert" evidence was, predictably rejected on that point.
"Civilian" is "a
person who is not a
member of the
police or the
armed forces" Definition taken from The Cambridge Dictionary. Agree with it or not. Many armed forces personnel past and present believe it's only them who can be not deemed civilians. Not true. And anyway, the police or armed services when off duty are treated in any operational incident as civilians, although the course the law takes after that might differ from non-police or non-service personnel. But that's another matter.
I do love a thread where people chuck in their opinions without checking facts. Jolly good fun.
As for drinking when using firearms, that's a different matter. I doubt many stalkers drink whilst stalking. However, in many circles mostly, but sadly not all in the past, having a port, wine, sloe gin or whatever at points during the day was the done thing when doing some "social" field sports. At it's least problematical, it'll lead to you not shooting as well. And whilst a small drink at, say, lunchtime might well not affect things terribly, there's always those who it affects badly, or those who will over-indulge. So, really, not a good thing.
Anyway, drive around or even be driven around in a state of drunkenness with your guns, loaded or not and the likelihood is, if caught, you'll loose your tickets, whether you get charged with anything else or not. So it's all a bit academic.