You might be surprised to find that so-called emissions defeat devices aren't actually illegal, but the government has just announced new rules to fine car manufacturers who sell vehicles with the devices that are intended to cheat emissions tests up to £50,000.

The tough new rules are designed to prevent a repeat of the Volkswagen Group Dieselgate scandal, which saw diesel vehicles from the group’s Volkswagen, Audi, Skoda, Seat and Porsche brands using special engine software that was specifically designed to cheat emissions tests by switching to less powerful but more environmentally friendly engine modes during lab testing.

Although the German company and some key executives were prosecuted in the United States, VW has said that it did not break any laws in Europe. However, the firm has recalled the affected vehicles and lawyers in the UK are preparing a case against Volkswagen on behalf of thousands of disgruntled customers.

More Dieselgate news:

The Department for Transport (DfT) says its new measures, which will see manufacturers face five-figure fines for any breach of the rules, have received ‘overwhelming support’ during the consultation period. According to the organisation, the new measures will be laid in Parliament before being introduced on 1 July.

Transport Minister Jesse Norman said: ‘There has rightly been a huge public outcry against car manufacturers that have been cheating on emissions standards. Their behaviour has been dishonest and deplorable. These tough new regulations are designed to ensure that those who cheat will be held to proper account in this country, legally and financially, for their actions.’

The government has also promised to end the sale of conventional petrol- and diesel-powered cars and vans by 2040, and says it will soon reveal a range of further steps that will outline the UK’s ‘transition to zero-emission vehicles’.