well, a few reasons really...

1. In the St.Margaret's village area, "commuter traffic" is not a problem. Sunday nights are not the time for commuters to travel into London for work - it's Monday - Friday, 8-6. And yet a Sunday night is heaving in St.Margaret's village - not a space in sight. Yet Monday - Friday daytime, I can park outside my house (on Winchester Road).
2. Why should we pay more for owning a large engine/old car. Aside from the fact that CO2 emmissions are NOT linked to climate change (did anyone else see that documentary a few months back on Channel 4 or was it just me?!), it is simply not fiar to charge in this way. I own a "gas-guzzler", yet I drive an average of 3,000 miles per year. 90% of the time my car is PARKED and not emitting anything! Compared to an average 11-12k per year in an average 1.6 litre engined car, I actually emit LESS CO2 per year, yet pay MORE. Just becuare my car is parked. I hardly think that's fair...
3. Junction safety has been cited as a reason for the CPZ. This is not the case. What's wrong with putting single yellow lines on corners. It would mean the junctions are clear of cars, and woundn't cost us any more than we are currently paying in council tax