An analysis of the maintenance records of 88,000 vehicles leased by the Lex Service group to hundreds of companies also showed that in a year there were nearly 25 mechanical breakdowns per hundred cars. That compares with a figure last year of 20.
Most surprisingly, cars made by Toyota and Nissan were found to have differing rates of reliability between home-made and imported models. The 700 Carina Es on the fleet built at Toyota's Burnaston plant in Derbyshire last year suffered 23 breakdowns per 100 vehicles compared with 5.8 for the imported Corolla model.
On average, Toyota recorded a reliability rate of 16.4. However, the company challenged the results. Toyota yesterday pledged to launch an investigation into quality standards at its Burnaston plant where the new Avensis model is made. Sources close to the company also said the Lex results may have been unduly affected by a batch of faulty spark plugs last year.
Garel Rhys, motor industry professor at Cardiff University, said that the very high standards demanded by the Japanese public may account for the much of the difference. "Historically, Japan has had the best-quality components and production methods," he said.
Nissan was also hit hard by the results. The Primeras produced at Sunderland had a breakdown rate of 23 per 100 cars. This compared badly with Nissan's imported Almera, which suffered only 1.1 breakdowns per 100 vehicles. A spokesman for Nissan said that its own research showed that the Primera breakdown rate was in fact only one-fifth that of the survey's.
Mitsubishi turned out to be the most reliable manufacturer - recording only 5.8 breakdowns per 100 vehicles. Citroen proved to be the worst - with a figure of 44.
According to the research, Mercedes' latest C-Class is less reliable than the model it replaced, the 190, which showed only one breakdown per 100 vehicles. Experts say this is not unusual. "With a car that is a few years old it is always being refined. With a newer car there are always little things that gradually get put right," said Bob Procter, the RAC's technical service engineer.Reuse content