David F wrote:

I live in Islington, and although all the journey planners seem to
think the best journey is an hour and a quarter through the City,
Brixton, Purley etc. From experience, this is gernerally a bad idea -
especially at the time I am travelling - so I thought the A13 out to
the M25, round a bit then on to the M23 would be much faster.

I live in Hackney near Islington border and frequently drive to Brighton.
I go east to pick up the A102 (or whatever that motorway class bit was
called) at Hackney Wick , south down thru Blackwall Tunnel, down the fast
A2 to M25 then round to M23. This is usually a nonstop drive and you're
going against the main flow in the tunnel.

E.