"Iain" wrote in message
...
"Martin Underwood" a@b wrote in
:

There are two ring roads around London.

Three. Besides the M25 and North/South Circulars, there's the inner ring
road, which is currently (almost) co-incident with the outer perimiter of
the congestion charge zone. Much like the North Circ used to be (and the
South Circ still is), it's a collection of roads that happen to form a
circumference around "central" London, rather than being a purpose-built
ring-road.

True. I don't tend to think of Marylebone Road / Euston Road / City Road as
being a ring road, but looking at a map it is. I suppose you could continut
it into south London as Borough Road, Westminster Bridge, Victoria Road,
Park Lane and Edgware Road to get back to the starting point.