In article , John Rowland
wrote:
As a child in the 1970s I noticed from
maps that the Hook junction was the only "wrongly designed"
junction in London, because it was blindingly obvious that the
Esher Bypass should have access to and from the Hook roundabout,
and the Esher road (A309) should lose access to (and possibly
from) the Hook underpass. I have never found out why it is the
way it is.

I think it was something to do with restricting traffic down through
Chessington. IIRC M25 does not appear on any of the signs there
although it's a natural route if you're heading S or SE

--
Tony Bryer