The SMMT has branded findings of showroom sexism as “absolutely unacceptable” following an undercover report by What Car?.

Using hidden video cameras, the magazine sent men, women and couples into 45 dealerships across England. They shopped for five new cars – a BMW 320i, Ford Focus, Nissan X-Trail, Vauxhall Corsa and VW Beetle Cabriolet.

Women were quoted an average of £534 more per car, and in one case, £1,800 more than their male counterpart. In addition, more than half the female shoppers and couples felt finance packages had not been fully explained, compared with 27% of men.

Christopher Macgowan, SMMT chief executive, says: “Approaching a new car buyer differently on the basis of their sex is absolutely unacceptable. Women influence around 80% of car purchases so it isn’t in a dealer’s interest to treat a huge customer base poorly.”

He adds: “The industry is united in developing a robust new code of practice to give customers peace of mind.”

Sue Robinson, director of the RMI’s National Franchised Dealers Association, says she is astonished at the findings. “For any business not to acknowledge the size of female buying power is extremely short sighted.”