Valuing used imported cars for insurance purposes promises to be a great deal easier with the launch of the first official trade prices guide for the sector.

Despite opposition from manufacturers and many UK dealers, unofficial, or "grey", imports began trickling into Britain ten years ago, according to CAP, which produced the price guide.

However, the trend really took off in 1997 and today there are an estimated 200,000 "grey" imports on the roads.

"The need for a professional trade book is critical," said CAP general manager Andrew Wilkinson. "Unofficial imports, most commonly from Japan, often have crucial differences in specification and value. This means anybody exposed to their values, including warranty and insurance providers, needs authoritative information on identification and market price."