Continued consolidation in the automotive retailing market means that groups now control over 71 per cent of the country's new car outlets and 25 per cent are owned by the top 20 dealer groups.

Research from analysts Sewells found that carmakers now rely upon dealer groups to retail vehicles more than ever.

Mercedes-Benz has the highest group presentation of all franchises at 98.6 per cent, followed by Audi with 97.6 per cent.

Skoda and Suzuki had recorded a rise in dealer group representation, while smaller franchises, such as Proton, Daihatsu and Subaru, were less attractive to dealer groups, Sewells said.

Meanwhile, the study also found that the revision to the block exemption regulations had failed to ignite franchised dealer interest in attaining authorised repairer status with manufacturers.

The number of authorised repairer sites only increased by 123 between 2005 and 2006.

Sewells said that the high volume brands had achieved greater success in attracting independent repairers to their networks.

Ford has the biggest authorised repairer network in the UK with 99 sites, followed by Citroen with 66 and Vauxhall with 63.