The technology – which is available to order from this week – is being offered on the A1/A1 Sportback and A3/A3 Sportback in specific 1.4-litre TFSI petrol models, making them attractive alternatives to the 2.0-litre TDI diesel variants.

The CoD System was debuted on the S6, S7 Sportback and S8 models last year and has also now been launched for the RS 6 Avant and RS 7 Sportback. In the new A1 and A3 models, it switches virtually imperceptibly between two and four-cylinder modes in as little as 13 milliseconds to optimise efficiency but still offering immediate access to the full 138bhp of power when required. An engine start-stop is also included.

The new CoD models are being offered alongside the standard 1.4 TFSI 120bhp versions and will carry a premium of £850. For this price, fleets can benefit from improved performance as well as improved fuel costs of up to 60mpg.

Meanwhile CO2 emissions of 109-113g/km for the A1 models and 109-112g/km for the A3 versions offer BIK savings of up to £919 for a 40% tax payer driving the A1 and £1,044 for the A3 compared to their 2.0-litre TDI counterparts.

The A1 and A1 Sportback COD models will be equipped initially with the seven-speed S tronic twin-clutch transmission, while the A3 and A3 Sportback versions have a six-speed manual gearbox. Both transmissions will however become available for all A1 and A3 CoD models later this year.

The new engine is offered with Sport, S line and Black Edition specification for the A1 and A1 Sportback models while in the A3 and A3 Sportback, it is available in SE, Sport and S line versions,

Prices start at £16,740 for the A1, £17,360 for the A1 Sportback, £20,055 for the A3 and £20,675 for the A3 Sportback.