The UK government has been urged to launch a probe into the practices in the car industry after it has been revealed that German car giant Volkswagen has been cheating in emission tests.
According to Penny Woods, chief executive of the British Lung Foundation, most new cars do not meet the European emission standards in the real world.
"Although the Volkswagen scandal is particularly astounding, the problem of unreliable emissions data runs deeper than the actions of one manufacturer," she said.
"Compulsory, independent, real-world testing is therefore essential, so that consumers have trustworthy, accurate information on the pollution and health risks of their vehicle before buying."
The US Environmental Protection Agency revealed last week that Volkswagen vehicles have been equipped with software allowing the cars to produce less emissions during testing than during actual driving. The real levels of nitrogen oxide pollutants produced by the vehicles have been said to be up to 40 times the legal limits.
In April this year, Supreme Court justices in London ordered that 'air quality plans' to comply with European Union law on limits for nitrogen dioxide must be submitted to the European Commission by the end of the year.
The lawyer who represented environmental group ClientEarth in court, Alan Andrews, said he was not surprised by the Volkswagen revelations.
"We have always known diesel is a killer and now we have a smoking gun," he said.
"We want to see the UK Government launch an immediate investigation to see whether cars driven on Britain's roads are cheating on EU air regulations."
The scandal comes in the wake of Government proposals to restrict diesel cars from going into city centres.
Steve Gooding, director of motoring research charity the RAC Foundation, warned that the UK's 11 million diesel drivers would be confused by just how much technology to make the vehicles cleaner has improved.
He added: "It is ironic that while diesel cars have been under scrutiny from politicians for air quality reasons the biggest blow to their reputation might have come from a company that makes millions of them.
"We know diesel cars don't perform as well on the road as in the lab but this has been put down to the limitations of the test cycle rather than possible manipulation by manufacturers.
"The whole testing regime is currently being overhauled. This fiasco shows how urgently that overhaul is needed if trust is to be restored."