Despite the best efforts of 'the great British summer', the growing range of Audi A4 Cabriolet models already finds over 4,000 homes in the UK each year more than anywhere else in the world.

The forecast for the design icon looks brighter still, because the latest line-up features newly upgraded engines and gearboxes and the addition of two attractively specified new models, bringing the cost of open-top luxury down to £24,545 OTR.

It will also soon include two new quattro four-wheel-drive versions, which will be open for ordering within weeks.

With the addition of new 1.8 T and 2.5 TDI versions to the original 2.4 V6 and 3.0 V6 line-up, and the imminent arrival of 1.8 T quattro and 3.0 V6 quattro versions, the A4 Cabriolet range is set to become the most comprehensive in the sector.

All models are available in standard or sport form, and following the recent revisions, all V6 petrol and TDI versions are now equipped as standard with a six speed manual gearbox.

The automatic alternative the much praised and still unique multitronic Continuously Variable Transmission (CVT) is an option for the majority of models costing £1,450, and has now been upgraded to include a Sport model that holds each of the six pre-set gear ratios for longer under acceleration to maximise performance.

The latest version of the A4 Cabriolet, fitted with the Audi 2.5-litre V6 TDI engine with 163PS, remains Britain's only diesel-powered convertible model, and thanks to a number of recent modifications now comfortably meets stringent EU4 emissions standards, eliminating the 3 per cent diesel tax premium for business users.

Both manual and multitronic CVT versions of the A4 Cabriolet 2.5 TDI can accelerate to 62mph in 9.9 seconds and reach top speeds of 140mph and 135mph respectively.

At the same time, both are capable of covering up to 39.4mpg (combined cycle), and do so with a competitively low CO2 output of 194g/km. As a result, the A4 Cabriolet 2.5 TDI is the cleanest, and therefore most tax efficient, diesel automatic in the sector. The A4 Cabriolet 2.5 TDI is priced at £26,920 OTR, with the multitronic version at £28,370.

The new A4 Cabriolet 1.8 T is the other newcomer, and with 163PS and peak torque of 225Nm, very closely matches its smooth 2.4 V6 petrol counterpart in terms of performance, delivered with the unmistakable punch of a turbo-four. With a five speed manual gearbox, it is capable of accelerating to 62mph from rest in 9.4 seconds and can reach a top speed, where permissible, of 140mph. Its keen performance is combined with competitively modest fuel consumption giving up to 33.2 mpg on the combined cycle, and relatively low CO2 output of 204g/km. The A4 Cabriolet 1.8 T is available to order for £24,545 OTR.

Standard equipment for all A4 Cabriolet models includes 16-inch '5-arm Aero' alloy wheels, an electrically operated hood, remote control central locking activating an alarm with interior microwave protection, electronic climate control, a leather 4-spoke multifunction steering wheel and a Concert stereo with single CD player.

An automatic roll-over protection system also adds to the extensive list of safety features already fitted to A4 saloon and Avant models.

Sport versions gain striking 17-inch '5-spoke star' alloy wheels with 235/45 R17 tyres, sports suspension, a sports leather steering wheel and sports seats with electric lumbar support adjustment.

The new A4 Cabriolet range takes over from the instantly recognisable original, which was first introduced 11 years ago. Britain was its most successful market, accounting for over 8,000 sales before production ceased in 1999, and it looks likely that history will repeat itself as the A4 Cabriolet grows in popularity.

Audi's A4 Cabriolet

Unique quattro four-wheel-drive models available from autumn 2003

Six-speed manual transmission now standard for all V6 models

New Sport function for multitronic CVT automatic transmission

New 1.8 T petrol (£24,545 OTR) and 2.5 TDI (£26,920 OTR) models

2.5 TDi engine achieves full EU4 compliance, eliminating 3 per cent additional tax burden for business users