Your vehicle is old. The vehicle is now collecting dust and dirt on your driveway or in a garage.
You are looking for a new vehicle. Your old car is not in good enough shape to be sold.
Your car has been written off. You have been involved in an accident and now the car is not roadworthy.
The MOT is void. But the work needing done to the car is too high for the value of the car. So is simply not worth doing.
Your want some extra cash. Maybe could be used to put towards a new vehicle or a gift.
Contribution to helping make the planet greener. By scrapping your old polluting vehicle, you are helping.