"PP - At the City Hall seminar last week the TfL representative said that most traffic using the Blackwall Tunnel either starts or finishes its journey in London and that there isn't much long distance through traffic that "should use the M25". I haven't seen any actual stats though." Thanks for the note. This worries me. Why? Because that's hardly 'news' and doesn't address the root cause (which I truly believe they don't know themselves). The tail is wagging the dog on this one, and you can bet that some significant lobbying's being undertaken by those who would secure the contracts to do the work. Ultimately national, regional and local government needs to understand why so many single-person journeys by car are required. At a guess its because public transport infrastructure is insufficient, inflexible and too expensive. If they don't ask travellers what it would take to do something different in their travelling habits and then address them, the best they can do is guess and force us to pay billions to fund their next folly.