The overall winner is the Electrolux Workzone stair and car vac, which provides great cleaning power at a mid-range price.
However, it does have one major drawback: the lack of a cordless function.
Despite the long power cable, which can always be boosted further using an extension lead, this will limit the cleaner's appeal to those who can bring their car close to their home.
For those who need a cordless function, the JCB 16.8V Rechargeable Vacuum Cleaner provides an effective alternative.
Finally, a warning: it's also clear from our testing that there are many cleaners out there that are do little more than pick up very loose surface dust.
Rather than spend your money on one of these, if at all possible we'd recommend buying an extension lead and using your home cleaner on the car.
What Car? winners
Best overall Electrolux Workzone stair and car vac
Best under 30 Halfords Cordless Re-chargeable Vacuum
Best 30-50 Electrolux Workzone stair and car vac
Best money no object Dyson DC16 Animal
What Car? ratings
1 Electrolux Workzone stair and car vac
2 JCB 16.8V Rechargeable Vacuum Cleaner
3 Dyson DC16 Animal
4 Halfords Cordless Re-chargeable Vacuum
5 Black & Decker Dustbuster Pivot
6 Black & Decker Dustbuster auto
7 Dirt Devil high power cordless handheld
8 Halfords 12V Car Vacuum Cleaner
9 Halfords Cyclonic Wet and Dry Car Vacuum
10 RAC 12V Wet & Dry Vacuum Cleaner