Yesterday morning's incident was unusual because it only involved speed and not a sudden lane change as well. It's six in the morning, and the M40 is pretty quiet. I'm in the outside lane overtaking a lorry, which in turn in overtaking another lorry. In the distance I can see a Mercedes S class approaching at some speed. It's pretty clear I won't have passed the lorry by the time it reaches us, but it's not showing any sign of slowing down.

In the end, the smartly suited driver leaves his braking so late I thought he was just going to run into the back of me. He had to brake so hard that his car began to submarine and veer about, one moment threatening to hit the central crash barrier, then next to run into the back end of the lorry. Suddenly, instead of lounging with one hand loosely on the wheel, he's sitting bolt upright grabbing it with both hands.

I tear my eyes away from the rear-view mirror, finish overtaking and pull back in. A few seconds later, the Merc driver emerges past the lorry, lounging again, and glares at me as he accelerates off into the distance. I feel pretty rattled. I've come pretty fucking close to being run off a virtually empty motorway, and there was nothing I could have done about it. The driver of the car who nearly hit me seems unruffled and has just charged off into the distance. The situation shouldn't have arisen and could have been avoided without this tossbag ever dipping below the legal speed limit. Madness.