With a cough and a splutter, the conveyer belt creaks into action and the cars slowly begin their final journey.

In just seconds, they have been turned into tiny pieces of metal by the giant shredder. The scrap is then separated out by giant magnets.

Surrounding the giant machine, piles of different metals sit ready to be collected.

Some 200,000 cars are recycled by Sims Metal Management in Avonmouth each year and 85 per cent of the car is recycled.

The Authorised Treatment Facility (ATF) in the Royal Edward Dock was the first such facility set up in the UK when new legislation concerning how to deal with cars at their end of their life was introduced in 2007.

To achieve the recycling targets of this legislation, cars have to go through a number of processes when they arrive here.

Because of the new vehicle discount or scrappage scheme, Sims has seen an increased number of cars arriving at the ATF, some sent by dealerships, and others driven straight to them by owners who then hand over the paperwork and leave in another car or catch the train back home.

The scrappage scheme is a voluntary scheme for motor dealers that begun last month. If a dealer joins it will give you £2,000 off a new vehicle if you let it scrap your old one. The scheme is due to run until March 2010.

"People take it for granted that when you scrap your car, it goes into a cube, but that's not necessarily the case," says Simon Palmer, Sims end of life vehicle manager who is responsible for the Avonmouth ATF.

"We have seen an uptake in vehicles coming here since the scheme began and we have set up good relationships with dealerships across Bristol."

The Sims facility at Avonmouth has the necessary infrastructure and systems to ensure it can recover hazardous materials from the car to the requirements of the new Government legislation.

Once a Certificate of Destruction is issued, the DVLA removes the vehicle from its database and ensures you no longer have any legal responsibility.

Down the road from the shredder is where cars first arrive.

Here, they go through a process called "depollution". They are hoisted up and then all the fluids still inside – petrol, diesel, brake fluid, shock absorber fluid, oil, coolants and water – are drained off or vacuum-sucked out. The battery and tyres are then removed and sent for recycling.

Depolluting takes about 45 minutes, and when completed, cars are taken outside to the yard where a giant claw rolls them over, removes the catalytic converter from underneath, and then turns into a giant fist to smash down and make the car as small as possible, so more vehicles can fit inside the lorry that then takes the cars to the giant shredder. This shreds the entire vehicle into tiny pieces. On the reclamation site, the sound of scraping metal fills the air. It is noisy and dirty.

Steam comes out of the 55-tonne shredder as a 6,000-horsepower motor rotates its blades at 500 revolutions per minute.

"The metals come out in a few seconds," says engineer Ivan Williams from Weston-super-Mare. "All you hear is a 'whoosh!' You wouldn't want to be in there. It's brute force. It's not technical."

Once shredded, the material passes through various stages of separation which separates the material out into ferrous metals, non ferrous metals (such as aluminium and copper) and plastics. Rotary magnets, air cyclones and eddy current separators are used in the process which separates the material at a rate of more than 200 tonnes per hour.

Mr Palmer, who has worked for Sims for 15 years, said once the materials are separated, they are sold on for use in manufacturing a whole range of new products, including cars.

On the other side of the road from the shredder, 25,000 tonnes of steel is piled up next to the dock, ready to be collected by huge ships that arrive once a month and take it away to countries such as China and Turkey.

The plastics are sent to one of Sims Metal Management's specialist facilities in the UK where the material is cleaned and separated into plastics for sale. And the non-ferrous metals are sent to a specialist facility where they are refined for use in manufacturing new products.