A new report from the parliamentary Transport Committee claims the Government should investigate and consider prosecuting Volkswagen for its emissions deception, but it has been far too slow to act.
On the Volkswagen scandal, chair of the Transport Select Committee Louise Ellman MP said: "Volkswagen Group has acted cynically to cheat emissions tests which exist solely to protect human health. Volkswagen's evidence to us was just not credible but the Government has lacked the will to hold VW accountable for its actions. There is a real danger that VW will be able to get away with cheating emissions tests in Europe if regulators do not act.
"Vehicle owners have been refused goodwill payments. That is despite VW inflicting a great deal of uncertainty on its own customers along with the prospect of declining residual values and the inconvenience of having to undergo repairs.
"We are concerned that VW's fix was developed at the lowest possible cost which might lead to increased costs for motorists down the line.
"We have called upon the Vehicle Certification Agency to do everything in its power to ensure that does not happen."
The committee welcomed the planned introduction of 'real driving emissions tests' and a stricter lab test for measuring fuel consumption.
It was disappointed that legal emissions limits were not set lower given the scientific evidence that shows dangerous NOx emissions could be cut much faster.
Ellman said: "Many of the European type approval reforms will reduce the opportunities that manufacturers have to cheat emissions tests. That is to be welcomed.
"But as vehicle technology becomes more advanced, what is most urgently needed is a robust regulator who can keep ahead of developments in technology. That regulator does not exist today.
"The VCA must make scrutinising manufacturers for non-compliance and questionable practices its first priority.
"We are concerned that manufacturers have far too great a say over how type approval reforms are implemented. There is strong evidence that vehicle manufacturers have employed a wide range of practices that are, in effect, defeat devices by another name. We have called upon the Department for Transport to be transparent in how it works with manufacturers to prevent both the spirit and the letter of the law from being broken.
"The vehicle testing and certification system is notoriously opaque. That has resulted in the VW emissions scandal. We have commended the Department for Transport on its commitment to spot check vehicles on the market. If that had been done properly in the past the likelihood of the emissions scandal from occurring in Europe would have been significantly reduced.
"We have also called upon the Department to ensure future in-service surveillance is improved by combining it with a commitment to make its results and supporting data publicly available for additional independent scrutiny."