Great Western Coffee Shop

I have mixed feelings about this.
Knife crime is a growing problem, and we should in theory welcome measures that assist in controlling such crime.

On the other hand, when I was working in London as a maintenance engineer I often carried around knives or other bladed articles as part of a tool kit. Carried either from one work place to another, or to/from home.
I believe that carrying such articles was legal as use in my employment was a "reasonable excuse" for having a knife or bladed article in a public place.

I carefully avoided Liverpool street underground station when a knife arch was in use at that place, making use of a bus, a taxi, or walking so as to avoid the knife arch.
Whilst I believe that I was not breaking the law, I was reluctant to take the risk that a police officer might take a different view.
Being arrested for "carrying a knife" would have been most troublesome, even if later acquitted in court. A court case could entail significant loss of earnings, and possibly legal expenses also.
Being acquitted is little consolation if one has in effect been "fined" two days pay, and spent a few hundred pounds on legal advice. Enough such acquittals could have ruined me.

Saw this article earlier, I'd love to have a bit more detail. Like did everyone coming through the entrance and exit barriers on P3 (as that is where it looks like it was, not the "entrance hall" as the article claims) have to go through it? What about the consequences of delaying people (e.g. if someone missed a train because of the extra time taken by this what would happen)? What about people with (potentially large amounts of, or just bulky) luggage?

When the police do these sorts of things they usually pick folk at 'random' rather than have eveyone go through.

Police's definition of random that is.

Having seen pictures of the sorts of knives these people carry I suspect it would take only a little bit of ingenuity to tell the difference.  Also there is a difference between carrying a knife on your person - that is a manner that is to hand and ready for use - and in a tool box or the like.  A chef might reasonably have a reason to carry cooking knives in an appropriate container for example.

I believe random people were selected, and were offered the choice of a body search or walk through the scanners

I think that's mostly how it is, probably, though I do know someone whose son is a chef and was prosecuted for carrying his kitchen knives in a cloth roll – standard chef style – on the way home after a late shift. However, I expect that not only the hour contributed to the decision to prosecute but also the attitude test. This was in London by the way.