[x] in English?

Hi y'all.

This isn't really conlang related, but I guess
it's no more unrelated than Greek vowels or
Swedish Princess Warrior Xina, so what the hey.

I've been watching a BBC production called=20
"The Childrens' Hospital" or "Alder Hey" or
something. Some people there (I've heard at least=20
three people use it) use a voiceless=20
velar fricative [x] instead of the stop [k] in=20
word final positions.=20
One example is the word 'back' which is pronounced
[b&x]. What's that? Is it some Gaelic influence
on northern English dialects or what? Although it=20
sounds pretty cool IMO.

Daniel