I NEVER felt the need for a dashboard camera – until I tried one.

Sales of dash cams have soared in recent years after car insurers started using footage as evidence in contested claims. Now social media, not to mention YouTube, is full of mini-movies uploaded by drivers from the front windscreen of their cars.

But if you’re a careful driver what’s the point of having one?

I drive around 1,000 miles a week on a huge variety of roads. Some of the bad driving I have seen has been breath-taking: cars travelling on the pavement to jump queues, buses shoving their way into traffic, impatient drivers ignoring red lights, idiots travelling at twice the speed limit… the list goes on.

If I have a small forward-facing video camera attached to my car’s windscreen recording everything in high definition when one of these danger drivers does something stupid I’ll have the law – and the video evidence to prove it – on my side.

Dash cams are so popular (sales are up by more than 400 per cent) that some manufacturers are designing them into new models. Earlier this year Citroen announced that the new C3 would become the UK’s first car to feature a fully integrated dash cam.

The technology has become commoditised to such an extent that it's now possible to pick up a dash cam for the price of a packet of fags. At the petrol station where I fill up there’s a stack of cheapo cams right next to the bunches of daffs and disposable breath testers.

Dash cams may be cheap but it pays to buy something better if you’re planning to rely on it to prove a potentially costly point. The last thing you want is lo-fi fuzzy footage.

The UK market leader in dash cam technology – Nextbase – has been around since 1999. Originally an importer of in-car DVD players (remember them?), Nextbase switched to dash cams when tablets and smart phones rendered disc-based movies redundant.

The 512GW is Nextbase’s latest camera. It replaces the award-winning 512G and boasts higher video quality, built-in wi-fi so clips can be reviewed on your smartphone without the need for a computer and GPS location logging.

One of the keys to the 512GW’s hi-def output is the new Sony image sensor which uses the same Exmor technology as found on digital SLRs and high-end smartphone screens. Nextbase places a six-element glass lens in front of this and tops it off with a polarising filter. Photographers will be familiar with the benefits of a polariser – less glare, deeper blues and a sharper-looking image.

The 512GW can shoot 1440p at 30fps – that’s better than full high definition – or 1080p at a smoother frame rate of 60fps. If you want to make longer recordings – or just make the most of a smaller memory card – the Nextbase also records at 720p and in standard definition. You can also switch the audio off and there’s even a time lapse option for really long journeys. I found the 720p setting to be the best compromise between space utilisation and quality.

Inside the box is the unit, the excellent click ‘n’ go magnetic mount, a car power socket plug (the cam has its own built-in battery, but that’s best kept in reserve for times when you can’t reach a power outlet), a CD with software apps, a sticker to warn drivers that they are under the watchful gaze of a dash cam and brief instructions.

The actual unit feels robust and well-made. Although it’s not particularly heavy it feels reassuringly hefty in the hand. You control the various functions by pressing resistive buttons either side of the small colour screen. The buttons are responsive but anyone with sausage fingers may find them a bit too close together.

Set up is a cinch and the windscreen sucker holds the dash cam securely in place (certainly more securely than my TomTom sat nav). The magnetic mount makes it easy to detach and stuff in a glovebox when you leave the car.

As you’d expect of a premium product the image quality is excellent. I was particularly impressed by footage taken at night when the sensor does a great job of picking out detail in the darkness. The footage is overlaid with a speed readout and location. The Nextbase uses its built-in GPS to calculate this data.

On the very first day of the test the Nextbase proved its worth when I approached a busy junction only to find a broken set of traffic lights permanently stuck on red. As I carefully inched across the road I did so confident in the knowledge that I had the footage to prove I was doing nothing wrong.

Since then the dash cam has been the perfect back-up buddy – silently recording my drives and storing the footage away on a 64GB SD card just in case I ever need it.