Diesel vehicles coming up to three years old may need professional attention to get through their first MOT test, warns the Retail Motor Industry Federation (RMI), which believes motorists may not realise how much attention diesel vehicles require in comparison to petrol-fuelled vehicles.

Ian Davis-Knight, RMI head of MOT and technical operations, says the MOT emissions test could damage a vehicle if it has not been well looked after: 'This test will not harm an engine that has been serviced and maintained correctly. However, if this is not the case, and the camshaft drive belt has not been changed when required, there is a possibility that damage will be sustained. You will be asked about the service history of the engine and whether the camshaft drive belt has been changed.

'The tester will not carry out a test on the vehicle if assurances on these points are not received. If the belt has not been changed, it is advisable to have it checked and replaced as recommended by the manufacturer.”