Alongside sliding towards a hard object, backwards, and realising that you aren’t going to be able to make it around the next corner, the double flash of a GATSO going off in your rear-view mirror is one of the most dreadful experiences you can have on four wheels.

It happened to me earlier this week, at five in the morning, on a section of the M25 on which I must have traveled at least a thousand times in the last 10 years, often at the exact same speed that I was doing this week.

The trouble with GATSOs, somewhat annoyingly, is that you can never tell which ones are switched on and which ones are switched off. Most of them are switched off, but this particular one – mounted on an overhead gantry between junction eight at Reigate and junction nine at Leatherhead going anti-clockwise – has been sat there for years, doing not a lot. 

Which is why, for years, I’ve driven past it at my regular quiet, empty motorway gait without so much as a dicky-bird by way of a flash.

Same goes for all the cameras on that section of the M25 between the M23 and the A3. For aeons, they’ve laid dormant unless a speed limit lower than 70mph has been posted due to bad weather or some such, at which point you’re a fool not to slow to within an mph or two of the posted limit.