95 per cent of all Diesel cars are breaking Nitrogen Oxide limits
A large number of cars are breaking official emissions limits, according to a study carried out in the wake of the Volkswagen diesel scandal.
Consumer group Which? analysed detailed emissions data from more than 300 cars tested in real world conditions since 2012.
Some 95% of diesel cars and 10% of petrol vehicles were found to emit nitrogen oxides (NOx) above acceptable levels.
The Jeep Grand Cherokee was the worst performer out of the 153 diesel cars tested as it emitted 15 times the amount allowed, the report concluded.
Researchers also found that two-thirds (65%) of the petrol cars tested broke limits on carbon monoxide emissions.
Despite the results of the study, all the vehicles complied with emissions regulations when undergoing official tests.
Tougher testing methods are due to be introduced from September next year but Which? is calling for this to happen sooner.
The organisation's executive director Richard Lloyd said: "Car emissions and fuel claims are important factors when buying a new car, so drivers will be shocked by the results of our testing.
"The current official tests are clearly not fit-for-purpose and we urgently need a new regime putting in place that reflects the reality of how we drive."
Volkswagen Group admitted in September that it fitted software to engines in a bid to cheat emissions tests. Some 11 million diesel vehicles are affected worldwide, including almost 1.2 million in the UK.