Prepare to be disgusted, seriously disgusted. But don’t worry, it’ll do you good, especially now that we’re all being urged to do our bit in the battle against coronavirus. Trust me, I’m a doctor.

OK, I’m not a real doctor. I haven’t got a medical qualification, only a PhD. And, OK, it’s in political rather than proper science.

I can, however, claim a degree of expertise in what I’m talking about — all of it gained from over half a century of painstaking observation of men’s toilet habits.

I tend not to waste too much time in the gents but this is the important bit – I never, ever leave without washing my hands.

It’s that last bit that makes me unusual, at least among men, according, that is, to a survey five years ago that suggested fewer than four out of ten men washed their hands after going to the toilet — a figure that rose to six out of ten for women.

These are not the only statistics available, it should be said. A Gallup survey of 64,000 respondents worldwide paints a slightly more optimistic picture, at least if you’re British.

Only 50 per cent of Dutch people surveyed said that they wash their hands compared with the super-clean Saudis at 94 per cent and 75 per cent of Britons (a figure, incidentally which puts us just about on a par with the Irish and the Americans).

Saying we do something, however, is not the same as actually doing it. What survey researchers refer to as “social desirability bias” — our tendency to give the responses we think we should be giving them rather than the ones that truly reflect our behaviour or opinions — makes it unlikely that three-quarters of us are actually doing what both personal and collective hygiene demands.

Indeed (and here’s where the half-century of participant observation comes in), I’d like to call (bull)shit on that figure here and now. I’ve seen what men do after they’ve zipped up or, even worse, done what my grandmother would have called “their business”. And it isn’t pretty. Many, maybe even most, blokes head straight for the door, after which, they’re presumably shaking your hand, giving you back your change, serving you food, etc.

Of course, actually getting out of said door in many cases involves pulling at some kind of handle. This is a nightmare for those of us who do observe the post-pee and/or pooh niceties, unless it’s wintertime and we’re carrying gloves or maybe wearing an overcoat with helpfully long sleeves.

It’s also the reason why, last week, a health information campaign featuring a dirty door handle was chosen after tests showed that 96 per cent of people remembered it, compared with 85 per cent recalling one that advised them simply to wash their hands. “Information works on a cognitive level. But disgust works on an emotional level,” a source (presumably not a source of infection) told The Times last week.

But are there more positive nudges that could be used in the battle to persuade us to do the right thing? Probably yes.

In an academic article, kindly provided me by a fellow Tweeter, the researchers not only confirm that a substantial minority of people (especially men) don’t wash their hands after using the loo but also take us through why it’s hard to get precise data on the topic, university ethics committees being unsurprisingly unenthusiastic about proposals that suggest setting up CCTV in the spaces in question.

More importantly, not least because more handwashing appears to reduce levels of respiratory illnesses by over a fifth, they explore some simple and cheap (in the best sense of the word) tricks and techniques to get us to wash our hands drawn from behavioural psychology and economics.

So what works? Believe it or not putting a decal of a pair of eyes on the mirror above the sinks has an effect: the fact that Big Brother (or sister) is watching you, and, what’s more, you know they’re watching, isn’t always a bad thing, perhaps.

If you’re not keen on surveillance, however, then try citrus as an alternative. Sprayed intermittently around the sink, it too appears to raise rates of handwashing.

And finally, lines of large, red, arrow-shaped stickers directing you, along the floor, from the stalls and the urinals to the sink, also encouraged people to do what’s good for them and what’s good for the rest of us, too.

You may laugh. Indeed, let’s hope you do. After all, you’re more likely to remember something funny than something purely factual conveyed with a wagging finger. But this is also serious stuff and with incidences of Covid-19 on the rise daily, we’re talking deadly serious.