It's a jungle out there. I got chatting to a chap this morning who rides Dorking to Westminster and he said that stretch was by far the most dangerous part of his journey. I think everyone I have spoken to on the CS7 has said the same, particularly the Tooting stretch. It not just the cars. the pedestrians (and some cyclists) are just as dangerous.
In the evening Epsom is also pretty dangerous but at least its only the cars and lorries you have to watch out for.
Crikey - Dorking into Westminster is a decent commute - must take him ages!