For me the Orcadian accent trumps everything else in the UK.
Used to work with a French guy who had studied in Glasgow, when we was daan saarth (surrey) together people thought he was a weegie soap dodger just like me…
Got good friend whose Italian and when she starts swearing you think you were in deepest darkest Dundee!
I believe the Liverpool accent to be quite distinct in that it bears no relation to those surrounding it; geographically speaking.
Also I find the borders accent the strangest as it sounds like English people who can roll their “r’s”.
Don’t get me started on the “Kelvinside” accent though, my mates mum used it all time fn annoying.