RESIDUAL values are being hit by the 'red devil', according to top leasing company British Car Contracts. This week the company warned fleet managers that auction buyers were running scared of cars equipped with so-called brain keys which access the engine management system of vehicles during servicing.

BCC says the red keys, which have been introduced by a number of vehicle manufacturers including Alfa Romeo and Fiat, have proved highly successful in improving car security and preventing the doctoring of engine settings - but among buyers at auctions they have become known as 'red devils'.

If a car is sold without a brain key buyers will be unable to service the vehicle properly and, as a result, such cars are fetching up to £600 less than a similar car sold with a brain key, according to auction expert Peter Lorimer. Some auctioneers, such as ADT Auctions and CMA, are now announcing 'red key is with the car', when the vehicle is about to be sold in order to allay fears of potential buyers.