Audi is planning to target volume manufacturers as well as arch rival BMW with its latest new model.

The premium brand has set its sights on customers from Ford, Vauxhall, Renault and Peugeot with an open-top version of the popular A3 compact model – and believes a fresh focus on diesel power will drive it to significant extra sales.

“The 1 Series Convertible is our main competitor, but our new Cabriolet offers something so different that we think it will also attract buyers from the mainstream sector,” said product manager Jo Elliott.

The first difference is based on a neatly engineered pressure pump and twin hydraulic cylinder mechanism that takes just nine seconds to fold down the fabric hood into a dedicated steel box at the touch of a button and only 11 seconds to fold it back out again.

Because the 260-litre boot area is unaffected by the hood position, rear seat accommodation offers ample legroom for average-height adults.

But Audi is banking on a choice of diesel engines to clinch 4,500 registrations this year and more than 5,500 in 2009.

Unusually, the 1.9 and 2.0-litre diesel cars undercut the 1.8 and 2.0-litre TFSI petrol versions by between £900 and £1,550.

Standard, Sport and S line models all have alloy wheels, air conditioning, power windows and CD sound as standard.

Specification:

Price: £20,750 - £27,060
Engine: 1.9 diesel, 105PS; 2.0, 140PS, 1.8 petrol, 160PS, 2.0, 200PS
Performance: 0-62: 12.3-7.3 sec; top speed: 115-44mph
Transmission: 5/6sp man or S tronic
Efficiency: 55.4-37.2mpg; 134-182g/km CO2
CAP RV: 3yr/30k ??%
Rivals: BMW 1 Series, Focus CC, Astra Twin Top, Megane CC, VW EOS.