The AA has criticised manufacturers for launching new cars without adequate parts back up. It says complaints from members over repair delays have risen considerably this year.

Members were forced to wait “a considerable time” for parts to be supplied, sometimes more than eight weeks for common items like wheel bearings, according to an AA spokesman.

“The standard of service from manufacturers is not good enough,” he said. “Consumers believe that manufacturers are great at making, marketing and selling cars, but they take less interest once the car has been purchased.

“They must look after consumers for the life of the car, not just until it is purchased.”

A rising number of model variants, with a wider range of colours and trim options, is at the root of the problem, intensified by manufacturers' reluctance to stockpile parts because of the cost.

“They get just-in-time deliveries to the production line, but they can't get them despatched to dealers in a reasonable time,” said the spokesman.

“As cars become more reliable, faults tend to be one-offs and cannot be anticipated. Manufacturers are less prepared and this is tarnishing the image of their products.”

Bodyshops have complained about lengthy delays on the supply of accident repair parts and panels. It has forced them to endure increased costs due to longer supply of free replacement cars and storage of the customers' damaged vehicles.

The AA spokesman dismissed claims by the SMMT that customer satisfaction was high and complaints low for servicing and repair work at dealerships.

“Consumer expectations are low – they believe that if they don't get ripped off then that in itself is a result,” he said.

A SMMT spokesman said the association was not aware of any problems with parts supply.

He added: “We are, though, concerned that this issue may become a problem if Block Exemption is not retained in some form. Manufacturers have set up huge warehouses holding parts for supply to dealers. This may change if Block Exemption goes.”