I have to say that having previously lived for many years in the borough's of Westminster and Kensington And Chelsea where,even with residents permits you have a snowball in hells chance of parking outside your home, (or even on your own street) That parking a few paces from ones front door is a luxury, and also not really a neccesity, I would rather forgo parking outside my house in favour of allowing local small independent businesses to thrive. I saw what CPZ's did to the trade in north kensington when they introduced them there (I think it was sometime in the mid-late '90's) and it really did kill local shops and pushed people to shop in Sainsburys on Ladbroke grove where they could park.
I am strongly against, for reasons previously mentioned.