The models, the A200d and A220d, use new OM654 engines that conform to RDE 2 emissions standards, not compulsory until 2020.
The engines are among the first to be RDE 2-compliant in the UK. As a result, business car owners will benefit from reduced benefit-in-kind tax: in 2017’s Budget, the Government announced there would be a diesel tax supplement of 4% for cars that do not meet the RDE 2 standard.
Diesel-powered A-Class models are expected to make up the lion’s share of the line-up’s sales. However, the diesel mix is expected to decline - in the last generation it accounted for 70% of sales - as a result of diesel falling out of favour.
The A200d is powered by a 2.0-litre diesel engine, producing 148bhp and 236lb ft of torque, while the 2.0-litre diesel in the A220d offers a 40bhp upgrade, and 295lb ft.
With both engines, the A-Class can achieve at least a claimed 65.7mpg on the combined cycle, emitting 110-114g/km of CO2, meaning that both are likely to continue outselling petrol variants.
The A200d will be available in two trims: Sport and AMG Line, while the A220d will be available only with the range-topping AMG Line package.
Sport offers a reversing camera, DAB radio, keyless starting and carbonfibre trim as standard, while AMG Line in addition includes a sports steering wheel, AMG styling elements and larger 18in wheels.
The A200d Sport will be available from £28,805, £3,660 more than the A180d SE. The A220d AMG Line starts at £30,005.