USED car values guide CAP Black Book celebrates its 25th year this month.

At launch in October 1979, the guide contained 4,000 prices across 140 pages while today it offers 500,000 values through 1,408 pages.

The company behind the guide said that today ‘CAP Clean’ is the universally acknowledged benchmark trade value for a used car in ready to retail condition. Black Book managing director Ian Bissell said: ‘We are very proud of the place Black Book has earned in the used car industry over 25 years.

‘In that time the demands of the market have changed from requiring a simple and general values guide for dealers to a benchmark pricing system used, for example, by all the major banks offering personal car loans or financing massive corporate fleets.’