In message , at 20:19:49 on
Wed, 6 Oct 2010, Yokel remarked:
There's a bit of the M25 near South Mimms that "used to be" something
else (A6 probably), before the plonked the M25 on top of it. At least
they gave non-motorway drivers a new alignment alongside (albeit a
B-road): http://goo.gl/maps/PFIN

It used to be the Rickmansworth by-pass. I once had a friend in King's
Langley and remember using this bypass long before the M25 arrived - I
wondered why it had a right-angled bend with an apparently unnecessary
roundabout and slip roads (now part of one of the M25 junctions). But
they obviously knew it was coming and so there had been some forward
planning.

That's a completely different bit of M25, about 15 miles away.
--
Roland Perry