Yes I was using western as synonymous with ASCII users, and it’s not. My bad.

£ is still just a byte

And yet it is reasonably common to see "£" when the UTF-8 is misinterpreted.

When using latin-1/latin-15/iso-8859-1/iso-8859-15/cp1252 that statement is true. With utf-8 it is two bytes (c2 a3), if a software uses utf-16, ucs-2, etc. it may be more.

Not in any modern encoding and certainly not in ASCII either. Having the highest order bit set makes that kind of problematic.

Nope, says UTF-8.

'u32_pound & 0xff == u32_pound' happens to be true, ye. It doesn't make it a byte. You need the leading 0s.

My mistake

For the UK, you also need to represent the Celtic languages. You'll need at least these letters: â, ê, î, ô, û, ŵ, ŷ, à, è, ì, ò, ù, ẁ (maybe ỳ?), á, é, í, ó, ú, ẃ (maybe ý?), ï (maybe more ¨), ...

Example: https://www.llyw.cymru/ (Welsh government homepage).

Bits of https://www.highland.gov.uk/press (Scottish Highlands council).

(I'll admit most people who don't speak these languages won't bother with the diacritics, unless it's as easy as typing English.)