Thirteen popular models were smashed into deformable walls to simulate crash conditions at the Transport Research Laboratory. Two main tests were conducted to gauge the protection cars gave to occupants and pedestrians in the event of front and side-impact crashes.
Only one car, the Volvo S40, was awarded a four-star rating in the tests - the highest possible under the Euro New Car Assessment Programme (NCAP) ratings. Five cars got three stars - the Ford Mondeo, Vauxhall Vectra, Volkswagen Passat, Nissan Primera and Renault Laguna.
The results showed that some expensive marques did not offer greater protection from injury. The pounds 20,000 Mercedes C-class only received two stars as did the pounds 17,000 BMW 3-Series.
The Mercedes, which is currently being redesigned, did particularly badly in the side impact test - where a car is rammed from the side by collapsible barrier at 30mph. According to researchers, when the test took place with the Mercedes "the [driver's] door struck the dummy's chest before the side airbag had fully inflated".
Edmund King, head of campaigns at the RAC, said the tests showed "price alone was no guide to how well protected a driver and passengers are. The lesson is the consumer cannot judge a car's safety on the price, manufacturer's reputation or advertising."
Other cars which only scored two stars included the Rover 600, Audi A4, Citroen Xantia, Saab 900 and Peugeot 406.
The results brought a furious response from the industry - aware that the public may shun cars that do not make the grade. In the last batch of tests in February, the programme ranked the Rover 100, a popular hatchback, as the worst for car safety. Sales from January to May this year were 32 per cent less than the corresponding period in 1996.
The Society of Motor Manufacturers and Traders condemned the tests as "trivial and misleading". Roger King, the society's public affairs director, said: "To star cars for safety on the basis of two different tests, ignoring other factors such as handling and braking characteristics is insufficient for accurate consumer guidance."
Mr King said the SMMT would not expect manufacturers to use the results in publicity material. Ernie Thomson, chief executive of the SMMT, said the industry had some "reservations about the tests" which he would discuss with the Government later this month.
The industry's comment brought a swift rebuke from the Consumers' Association, whose chief executive, Sheila McKechnie, called on the industry to stop "rubbishing the tests and undermining consumer confidence".
The test's supporters appear to have the upper hand. Neil Kinnock, the European Union's Transport Commissioner, welcomed the new tests and announced that the programme would be extended.
Describing the EU's annual 45,000 road accident deaths and 1.6 million injuries as "an appalling toll of tragedy", Mr Kinnock said road deaths could be cut by 30 per cent and the number of serious injuries reduced by half if all cars matched the levels of the safest models.
The survey findings will be published in What Car? and be made available to all 12 million RAC and AA members. However, the Government will not force dealers to carry the information. Baroness Hayman, the roads minister, said: "I believe people will research into the safety aspects of their next car as more information becomes available."