"HMRC criminal investigation officers have wide-ranging powers of arrest, entry, search and detention."
https://en.wikipedia.org/wiki/HM_Revenue_and_Customs#Powers_of_officers
Looks like they go after smugglers. What is your point?
So as I said. People are not jailed for it everywhere. Lots of times it takes extreme circumstances. That said you are morally obligated to pay taxes if you benefit from them.
I benefit from maybe 10% of the activities that my taxes fund. So I'm only obligated to pay those 10%? How about compensation for the 90% of tax activities that make my life worse?
You are not evaluating your benefits properly. The benefits that others receive directly do affect you indirectly. Living in a stable and prosperous area is a benefit.