Picture the scene. You've put your bike in your car and driven out to somewhere lovely to ride. We'd be the first to admit that this isn't an ideal scenario in all sorts of ways - it'd be far better to just ride from your house. But we're not going to pretend that this is in any way a perfect world. Lots, going on most, people drive to ride. Let us accept that and move on.

Where were we? Ah yes. You've ridden somewhere lovely but it was rather splattery underwheel, and now you're back at your car with a filthy bike. At this point you have a couple of options. Either you put the bike in the car, thus risking possibly terminal soiling of the upholstery, headlining or both. Or you put it on a rack on the outside of the car, which inevitably means that by the time you get home the wind will have dried the dirt on the bike into an almost impenetrable crust. Either way you arrive home with a manky bike, which is likely to be a nuisance, particularly if your domestic circumstances require you to keep your bike in your front room.

What's needed here is some way to clean your bike before it goes back in or on the car. You could take a bucket and brushes, but you'd need some water too. We know people who carry one of those hand-pumped garden sprayers in their cars, but they're not all that good at shifting dirt. There's always the trusty power washer, but they have a couple of drawbacks for use in the field - they need mains electricity and they have a prodigious appetite for water. And of course the power washer's ability to strip grease from bearings is well documented.

The Dirt Worker, then, could be exactly what you've been waiting for. It's a portable 12V power washer with an integral 13l (3.5 gallon) water tank. Fill the tank at home, put it in the boot and when you're done riding, plug it into your car's "accessory socket" (which is that thing that used to be called a cigarette lighter back when smoking was socially acceptable) and bingo - instant bike cleaning action.

Inevitably you don't get the paint-scouring grunt of a mains power washer, but that's probably a good thing. The Dirt Worker's 70psi jet has enough oomph to shift most gunge accumulations but not enough to damage any important bits of bike. It's also adjustable from a fine, wide spray (possibly more appropriate for watering pot plants) to a narrow stream. Somewhere in between seems to work best for most things.

The tank can hold enough water to do a couple of fairly grubby bikes or one very grubby one. If you just use the Dirt Worker and nothing else the bike'll probably dry with that characteristic recently-hosed patina, but that's nothing that a quick wipe down with a rag won't cure. We'd be tempted to stash some degreaser and a brush somewhere too for a more thorough (and more water-efficient) job.

It's got an impressively solid air about it, too. The main unit is sturdy moulded plastic with a comfy carry handle (which is important - the Dirt Worker weighs 6kg (13.2lb) empty but about 19kg (41.8lb, or one downhill bike) with a full tank). The power lead and water hose connect to the relevant ports on one end and can be stored in the handy nylon "pannier" that wraps around the unit itself. The actual trigger unit is comfy to use, with the aforementioned adjustable jet and a lever lock to save you actually holding the trigger - useful if your ride has left you with no ability to grip objects firmly.