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.
Because ultimately it's to their benefit. A minimum of £1.2bn to their benefit.
No wonder socialism in all its forms has always been such a failure, when it's cost-benefit analysis is done by people such as yourself & the maths genius known as the Abbottopotamus.
You're evading it even when the answer is handed to you on a plate. Why don't you simply admit that you don't have the slightest clue of what the real issues are and why the government may need to have direct control of security at events like these?
For no other reason than to wind up humourless vindictive little failures like you who seek to pull everyone else down to your level of shittyness.
You want them to pay for it? Fine: 100% of the income from the Crown Estate and other Royal holdings can now go directly to the Royal Family instead of 85% staying with the Treasury for general government spending.