YEARS ago I came up with a wheeze. And it was to do with two of my favourite subjects: trains and anti-social behaviour.

Travelling by train is an incredibly safe experience in Britain. Yes, there are occasional violent incidents but these are very rare. What’s more common than actual violence is rowdy and intimidating behaviour, and when you’re stuck in a carriage between stations with a group of loud, sometimes drunk, neds who are swearing, shouting and generally making everyone nervous with their behaviour – well, let’s just say it’s not quite the Orient Express experience.

If you have a mobile phone, you don’t want to use it to call the British Transport Police (BTP) because, as I say, you’re in a relatively small, enclosed space with these people and you don’t want them to turn their attention to you. Wouldn’t it be far better to have a BTP number that you could text surreptitiously, giving a code that would identify which train, and even which carriage, you are aboard? Everyone texts while they’re on a train so the troublemakers wouldn’t know you were alerting the authorities until the arrival of the officers.

Anyway, that was my idea, and when I became the minister responsible for the railways – and, at arm’s length, for the BTP as well – I suggested it might be a useful innovation. But the problem with being a minister is that no-one actually says to your face, “Don’t be ridiculous, minister – what a bloody stupid idea!” No, instead they invariably say “I’ll pass that on and see what can be done, minister.” (The corollary of this is that people always – always – laugh at your jokes. Oh, how I miss it…)

Anyway, into the black hole of ideas it went. I still think it might be a good, and rather inexpensive, way of making people feel a bit more secure aboard trains, especially women, and especially at night. So if it ever does emerge into the daylight as an actual system, just remember where you read it first.