The experts at the firm point towards cars such as the Vauxhall Adam and DS3 as examples of models where the "wrong" kind of cosmetic choices can have a dramatic effect on values.

Rupert Pontin, head of valuations at Glass's, explained: "Factors such as colour have always had a large impact on residual values but the trend towards increasing visual personalisation is magnifying the effect.

"You could have two Vauxhall Adams that are ostensibly the same on paper but, in the metal, are clearly hundreds or thousands of pounds apart in value because of choices that the original buyer made.

"There are some very cosmetically compromised cars around with colour, trim and wheel combinations that looked good to the first owner on the original order form but are not so attractive in the auction hall."

He added that one of the issues surrounding these cars was that the attractiveness of these vehicles was so subjective that it was difficult to know how individual buyers would react.

"The mauve supermini with a tartan roof and yellow wing mirrors running on 13-inch white alloys might look horrendous to a middle-aged man like me but great to a 17-year-old who has just passed their test.

"The problem is that the trade finds it very difficult to know how to value some of these vehicles so will tend to price them down in order to minimise the financial risk."

Pontin also had advice for fleets on such vehicles, saying: “When adding cars like this to their choice lists, fleet buyers need to take care that drivers are not specifying vehicles that may suffer from poorer RVs than you might expect. Fleet specification is not always good future retail specification."