ULEZ isn't perfect. I would like to have seen some kind of sliding scale e.g. concessions for pensioners, families, small businesses etc. (basically those who really depend on cars/vans and have limited financial means) but I would imagine it's virtually impossible to implement such a system. People would start registering their cars in their Granny's name etc. You probably want to target people who could use public transport and choose not to. Easier said than done and it doesn't help that public transport is unreliable.

I don't think the tube and buses are the problem in London - it's trains. They are bloody expensive for what you get especially compared to other countries. I took a train from Gdansk to Warsaw a few months ago and the fare was about £12 for a journey time of around 3 hours. Just checked and the cheapest fare from London to Manchester travelling today costs £76 and the journey time is only 2 hours. London to Clacton costs £41 and the journey time is only 1 hour 26 mins. Scandalous.