I wrote/posted this on Facebook earlier and it's good enough to copy here:
"In my travels today, I was unaware that Stapleford is so close to the border than one can simply walk out of Nottinghamshire.
I think this is the first time I've walked (not ridden) out of one
British county and into another; the last time I recall walking out of
any county was probably from El Dorado (California) into Douglas
(Nevada) in 2000 (which was also across state lines)."