I've been spat on, sworn at and forced off the road - and that's just by pedestrians. Cars, buses and taxis have driven at me, cut me up, swerved into my path and knocked me to the ground. During five years of daily cycling in Glasgow I have become accustomed to "almost dying" on a regular basis.

My efforts at retaliation are puny in comparison. I might roll my eyes and shake my head in the offender's direction. Once or twice I've mouthed an ineffectual "wanker". On another occasion, when a jeep driver took a fancy to driving into me three times within a 100m stretch of road, I made an official complaint at the police station across the road.

But no action, direct or otherwise, seemed to change the way some drivers (and walkers) in Glasgow treat cyclists. Until recently, that is.

For the past few weeks I have been wielding a shiny new weapon of defence: a helmet-mounted digital video camera. And I am not the only one. According to Action Cameras, one of the UK's leading sellers of such cameras, there has been a threefold increase in sales during the past year to cycling commuters. (During the summer, almost half of the average £10,000-a-week sales of video cameras - average price £200 - are to urban cyclists.)

Sab Jhooti, managing director, says: "When we launched the company in 2006, we mostly sold cameras to people taking part in extreme sports. They are great for filming clips of mountain biking and snowboarding, which people then post on the web. But in the past year, the biggest growth has come from cycle commuters. Rather than filming for pleasure, they tell us they want to film their routes to work as a form of evidence against dangerous driving."

It was "too many near-miss incidents" that led fellow Glasgow commuter David Brennan to attach one of the cameras to his cycling helmet. Brennan, a clinical scientist, regularly posts his commuter film clips on YouTube under the pseudonym Magnatom. Among his footage is evidence of a catalogue of dangers that face the ordinary city cyclist, including "brush-with-death" motoring incidents, inconsiderate and illegal driving, pedestrian misconduct, poor road surfacing - and even careless cycling.

Brennan, 35, says: "Although the camera has not changed my commute to any great extent, it does make me feel safer and calmer. Now, instead of screaming in annoyance at motorists, I simply point at my camera. It's amazing how quickly they back off when they clock it."

A video camera has also proved its worth for Winchester cyclist Paul McNeil after he was hit by a car. The 39-year-old, who posts on YouTube as "Tuneaftertune", suffered cuts, bruises and shoulder damage in an accident on the way to work. "Although there were witnesses, the footage made the claim much easier," he says. "I'm a member of CTC, so I contacted their solicitors after the accident and when they saw the film they were only to happy to pursue the claim."

But both cyclists make the point that footage is not meant to taunt motorists. In fact, Brennan believes that his YouTube films could "ignite a campaign to re-educate all road users".

I must confess to being a little disappointed not to have captured any major motoring incidents since I started using my camera, apart from a few car dodges and a couple of taxi swerves. Once, on a cycle/walk path, I came close to being knocked off my bike by something jumpy and yappy. But Lakeland terriers aren't much concerned by video gadgets.

Perhaps the most noticeable difference has been in what hasn't happened. A bus driver waved me past instead of doing the usual sudden pull-out manoeuvre, possibly because he noticed my filming potential. I'm also sure that a silver sports car gave me a wider berth after I tilted my helmet camera towards the driver.

Have I been witnessing a minor breakthrough in motoring/cycling etiquette? Or just experienced a few weeks of happy summer driving?