It amazes me that motorways function at all; thousands of cars each weighing well over a ton, hurtling along at 70-plus miles per hour, three abreast on a road that’s barely 20 metres wide. It requires every driver to implicitly trust every other driver; everyone has to follow the rules (the written ones and the unwritten ones) and everyone has to remain alert and fully in control. The consequences of just one driver failing to cooperate can be disastrous.

That’s why we take steps to ensure that everyone on the motorway is fully equipped for the task. We train them, we make them take a test, we test their eyes and their health, and we make sure that their sober. I’ll say that last one again. We make sure that they’re sober.

There’s another place where I frequently find myself, where the same conditions apply, although maybe less obviously so.

I fly a lot. I fly long-haul to visit our destinations and I fly short-haul for business meetings and conferences, and on every one of those flights I am also relying on the full cooperation and collaboration of every other passenger onboard.

Flying only works because everyone follows the rules and cooperates. We sit in our allocated place, we put our seat belts on and stay in our seats when we’re told to. We follow the safety advice and if we’re sat by the emergency exits we know that we have additional responsibility (even as passengers) to operate the doors if needed.

We follow the unwritten rules too.  We’re civil and well behaved and we respect the instructions of the crew. It’s so well drilled into us that we adopt these behaviours without even thinking about the consequences of anyone doing otherwise. A bit like motorway driving.

But then we do a very weird thing – we allow (encourage?) people to drink alcohol before they board a plane, sometimes with exceptionally dangerous consequences. Just this week we’ve seen a passenger sent to jail for threatening to open an emergency door mid-flight.

Even though she denied it, the court was told by the airline, Jet2 and by the police, that her behaviour was due to excessive drinking.

When discipline breaks down on a motorway, when a drunk driver swerves out of a lane or falls asleep at the wheel, there’s a good chance they’re going to kill themselves and often sadly, they’re going to kill or seriously injure others too.

But on a plane, on a plane full of hundreds of people, the consequences can be truly catastrophic. And if you think it can’t happen, think again. There have been thousands of air-rage incidents over the last 50 years – and it’s often only been thanks to the quick reactions of cabin crew and fellow passengers that disaster has been averted.

It’s reassuring to know, as I drive to an airport, that the person in the car next to me is almost certainly sober but when I board the plane there’s a good chance that the person next to the emergency exit door has already had a few drinks at the airport, and can readily have a few more during the flight too.

Earlier last year, when the government was tightening up the duty free rules, I wrote this: “I know that some colleagues in the industry will disagree with me. They will say (rightly) that the vast majority of travellers are sensible and shouldn’t be punished, but being drunk and disruptive on a plane should be as socially unacceptable as being drunk at the wheel of a car. I’m not afraid of flying, but I am afraid that one day a drunk passenger might bring down a plane. We should act now, before it’s too late.”

A few months later that warning has very nearly come true. It’s time to act.