Many motorists imagine that people carriers, also known as multi purpose vehicles or MPVs, are among the safest family cars on the road.

Simon Montague: "The wide variation in crash safety will shock motorists"

But the latest tests carried out by EuroNCAP - the European New Car Assessment Programme - show otherwise.

Eight people carriers were crash tested to see how well they'd protect the occupants in frontal and side collisions.

Renault Espace: top performer

All of them did well in the side impact test, but when it came to a front end crash, many performed poorly, or worse.

Bottom of the pack was the Chrysler Voyager, Britain's second biggest selling people carrier, and the car bought last year by the Prime Minister Tony Blair.

It achieved an "appalling" zero rating in the front impact test, with the risk of severe injury to the driver's chest and head, and very poor protection for lower legs and feet.

Other poor performers in a frontal collision include the Vauxhall Sintra, Mitsubishi Space Wagon, Nissan Serena and the Volkswagen Sharan (which is mechanically identical to the Ford Galaxy, by far Britain's biggest selling people carrier).

EuroNCAP chairman Max Moseley: "We all want our families to be safe and secure"

The best was the latest generation Renault Espace, the vehicle generally regarded as having pioneered the class when it was launched in 1985.

EuroNCAP said it gave "a well rounded performance" in front and side impacts. The second best performer was the Toyota Picnic.

People carriers now make up one in 50 of all new cars sold, but these results suggest that drivers who believe bigger means safer may find their faith is misplaced.

A survey for the AA showed 58% of drivers believed manufacturers put more emphasis on safety, and that safety is now the second most important factor for new car buyers, after reliability.

The independent crash tests are becoming increasingly influential among car buyers

EuroNCAP's independent crash tests were initially resisted by car manufacturers, but are now becoming increasingly influential among car buyers.

The results and star ratings have the potential to make, or break, a vehicle's safety reputation.

EuroNCAP chairman Max Mosley says: "We all want our families to be safe and secure and these latest results help to give the information you need to put your family's safety first."