The Guardian discusses "scrappage" for the UK.

Seems to me that this could (and should) be done, but with a far more aggressive green agenda.

Why not have the government give :
- £3000 to anyone scrapping their car and buying an electric one.
- £2000 for a small hybrid (accepts bio-diesel or alcohol)
- £1000 for a small, fuel efficient car
- £500 for anyone upgrading to any new car (on the assumption that new cars are more efficient)