The Alfa Romeo 166 has been named as Britain’s worst depreciating used car, holding just 14.4 per cent of its original used value after three years.

The findings make up part of Glass’s Guide of used car values, which has studied more than 6500 three-year old models available in the UK.

Despite no longer being on sale, Rover and MG cars also fare little better, with the Rover 45/MG ZS, City Rover and Rover 75/MG ZT completing the top four. These cars held just 20.3 per cent, 20.4 per cent and 21.3 per cent of their values respectively after three years.

All the cars in the top 10 worst depreciators all share one common trait, the fact they are no longer in production.

Adrian Rushmore, managing editor of Glass¹s Guide, said: “For almost all of them [in the top 10] the last year they were available to buy as new cars was 2006.

“The used-car market has been offering these models for many years and they have been overtaken by a younger generation of cars with more stylish, modern designs. In the case of Rover/MG-badged cars, it's not just the models that are obsolete - even the manufacturer has gone.”

The top 10 worst depreciating cars in the UK are:

1. Alfa Romeo 166 - 14.4% (of its original value held after three years)2. Rover 45 / MG ZS - 20.3%3. Rover CityRover - 20.4%4. Rover 75 / MG ZT - 21.3%5. Proton Impian - 22.0%6. Mitsubishi Space Star - 22.5%7. Nissan Terrano - 22.9%8. Alfa Romeo 156 - 24.2%9. Renault Laguna - 24.3%10. Cadillac CTS - 24.8%