Dozens of diesel vehicle models are being investigated over concerns their emissions are higher than thought, the Department for Transport (DfT) has confirmed.

The inquiry will initially examine 47 models produced by 20 brands, according to a Government response to a Freedom of Information request by environmental legal charity ClientEarth.

The dieselgate emissions scandal first surfaced against Volkswagen in 2015, when the company admitted around 11 million cars worldwide were fitted with defeat device software, which tricks laboratory tests into recording lower levels of toxic emissions than in real world conditions.

Defeat devices are illegal, misleading for drivers and can have negative health impacts on the public. We routinely and robustly check vehicles against emission standards and have acted quickly to set up an investigation on this matter

A Downing Street spokeswoman said the DfT was “aware of some manufacturers using defeat devices which are illegal and they have acted quickly to set up an investigation”.

This could result in thousands of cars being recalled.

The DfT said the models being investigated were a “high priority” because previous testing indicated they may be non-compliant with regulations.

The identity of the models has not been publicly released.

We will work with industry to resolve any issues identified

A later phase in the inquiry could see more than 200 models examined.

Any vehicles found to be in breach of emissions regulations would “require remedial action in order to achieve compliance”, according to DfT documents.

This would be paid for by manufacturers.

ClientEarth has written to Transport Secretary Louise Haigh calling on her to ensure the inquiry is conducted urgently and to publish proposals for tougher vehicle recall laws.

A DfT spokesperson said: “Defeat devices are illegal, misleading for drivers and can have negative health impacts on the public.

This programme of investigations represents a major step forward in addressing the lingering legacy of dieselgate. It represents progress towards the UK Government being able to hold manufacturers to account for emissions cheating practices

“We routinely and robustly check vehicles against emission standards and have acted quickly to set up an investigation on this matter.

“We will work with industry to resolve any issues identified.”

ClientEarth said in a briefing document: “This programme of investigations represents a major step forward in addressing the lingering legacy of dieselgate.

“It represents progress towards the UK Government being able to hold manufacturers to account for emissions cheating practices and, depending on how rigorously the investigations are pursued, could be the most meaningful step the Government has taken yet to lift the lid on the issue since the scandal broke.”

But it expressed concerns over “worrying gaps and weaknesses in the DfT’s plans”, adding that it was “not clear if the DfT will be acting with the required urgency”.