It's staggering to me that £46 billion goes to HM Revenue and Customs. So it costs £46 billion to administer £506 billion in tax revenue! That's almost 1/3 the budget of the entire NHS!
That doesn't seem like a good ROI at all. A product of an over-complicated tax system?
If you go back a year you can get some detail into what HM Revenue and Customs spends it's money on (90% of it is under the title 'social protection' which is child welfare and tax credits). The collection and enforcement looks like it costs 4 billion at most.
Tax credits deserve some scrutiny. A significant portion of tax revenue is effectively being paid as a subsidy to businesses allowing them to systematically underpay their staff.
I don't know what their actual budget looks like, but I do know that they're huge and have been making significant changes around digital transformation. That would result in high spending followed by later savings.
That doesn't seem like a good ROI at all. A product of an over-complicated tax system?