Come on
@Skylog , I'm looking forward to your answer. I'll even give you some help. Somewhere in the following photo is a clue as to why Theresa May might find it especially embarrassing to show up at the G7 meeting next month, and were something to have gone wrong, having to personally explain to another head of government as to why the UK didn't feel it was worth bothering to arrange for adequate official security for the event. We can even leave Her Majesty and immediate family out of your answer, as apparently you have already discounted them. I'm sure there are other examples in other photos, but we'll just stick with the simple ones here.
Or you could just admit that perhaps the people in charge of things in the UK might possibly have some clue of what they are doing while you have none.