Parkers overall rating: 4 out of 5 4.0

The TwinTop is offered with a decent engine line-up that kicks off with a 1.6-litre petrol engine with 115bhp and a 0-62mph time of 12.4 seconds. It's fairly economical with fuel economy of 42mpg, but it's more suited to cruising around town than higher speed driving. The 1.8-litre VVT has 140bhp and is eager enough, but does need to be worked hard for relatively small increases in speed.

On the plus side it is smooth and is the only engine available with an automatic gearbox - although it's a sluggish four-speed transmission. The five-speed isn't great though - it's awkward and needs a slow deliberate movement to make a clean gearchange. The 2.0T has a far better six-speed gearbox. It also has a considerable 200bhp giving it impressive performance for a convertible with a 0-62mph time of 8.3 seconds.

Only one diesel is available but the 1.9 CDTi is the pick of the range thanks to its blend of punchy performance and economy. 0-62mph comes up in 9.5 seconds yet economy is 47mpg compared to 30mpg in the 2.0T.

The TwinTop is an easy car to drive albeit far from thrilling. It handles precisely and corners well, but doesn't feel as involving from behind the wheel as alternatives like the Volkswagen Eos, hampered by steering which lacks feel. Body control is good, so it's a shame that the Astra suffers from body shake with the roof down. A Sport button fitted to top of the range Design model sharpens the throttle response and makes the steering feel more direct.