Several models of car are set to become more expensive in the Netherlands after new environmental impact tests showed they emitted more CO2 than previously thought.

The new tests were introduced after it emerged that manufacturers such as Volkswagen and BMW were using software to manipulate the results of their emissions checks on a massive scale.

Like its predecessor, the new Worldwide Harmonized Light Vehicles Procedure is a laboratory test, but imposes more ‘real-life’ conditions such as temperature and tyre pressure, making it harder for manufacturers to optimise the results.

The amount of CO2 in a car’s exhaust is a key factor in calculating bpm, a tax imposed on sales of all new cars in the Netherlands. A survey by market research firm JATO found that the tax on many models had risen by hundreds or thousands of euros.

In the most extreme case, the BMW X5 xDrive has gone up in price by €15,000 since last year. A typical mid-market car such as the Peugeot 308 SW (petrol engine) will cost an extra €2,100.

The motor trade association RAI and garage owners’ group Bovag has called on the government to revise the bpm tables next year to ensure car buyers are not penalised for a rule change triggered by manufacturers’ duplicity.