As someone whose farm is horribly spread out I spend a lot of time on the road in my tractor travelling between fields. Indeed, before the days of the mobile phone, my late father used to grumble: “If I’m searching for you there’s no point looking in a field – look on the A27!”

With so many hours spent trundling along stretches of busy tarmac I am familiar with how stressed other road users forced to queue behind me can become. Imagine my interest, then, in the news that car manufacturers are testing technology that illuminates the exterior of their cars to signal the mood of the driver inside.

Ford has demonstrated a Focus RS which has sensors that detect the driver’s pulse breathing rate and sweat levels. As the driver starts to get het up, lights in the car’s exterior bodywork start to flash, and virtual reality images of beads of sweat are illuminated on the windows. When the driver really loses it, the whole car body and windows start to flash white.

Think how useful this would be to me in my tractor as I approach a layby! All I would have to do is glance in my rear view window to see if any of the cars, vans and lorries queuing behind me have flashing bodywork or beads of sweat showing on their windscreen. If the percentage is high (or some whole cars are flashing white) I will immediately pull over. But, if all looks calm, I will be able to keep going to the next pull off, or even to the field I’m headed to, secure in the knowledge that no one behind me is getting stressed.

Without this technology, of course, modern drivers are already remarkably adept at letting me know the exact state of their emotions as they follow me in my tractor. There is the aggressive weave manoeuvre or the flash of the headlights or the intimidating technique of driving inches from whatever implement or trailer I’m hauling. And when I do eventually pull over I never cease to be impressed by the ingenious variety of stares, horn toots and language. In just the split second that it takes to pass my stationary tractor they convey exactly what they think of me for adding a couple of minutes to their journey time.

Ford claims that the new car will make driving safer as the car can send soothing messages to stressed drivers to lower their heartrates. But I can’t help feeling that nothing is as therapeutic to a driver on the point of combustion as giving me the sustained raised finger.