Choosing a green car and being a green owner isn't the end of the environmental motoring story.
Once your car has reached the end of its life - on average, when it reaches around 12 years old - it has to be disposed of carefully. There are plenty of noxious materials, liquids and gasses in a car that have to be collected, extracted and discharged before a Certificate of Destruction can be given to the last owner.
Unless you know your hexavalent chromium from your elbow and have an authorised treatment facility in your back garden, you're not going to be able to do this yourself.
Thankfully, the responsibility to take care of all this now rests with the original manufacturer of the car.
So, if you find yourself the owner of a motor that will be motoring no more, contact the manufacturer to find out where your nearest facility is.
If you own an MG Rover there's no one for the treatment facility to send any bill to. Currently, however, the price of scrap metal is high, so you could even get a little money for the motor from the treatment facility.