Tom Williams, the Harlequins wing who admits biting into a joke blood capsule to feign a cut mouth and let a substitute on, was clearly wrong on a number of counts – injuring rugby’s reputation as well as his own being just one of them – but I have to admit that my first thought when he was led off looking like a bulimic vampire with an eye twitch was only a man could make such a poor job of faking it.

Anyone who has brought up boys or husbands learns one thing pretty fast. Men make terrible liars. And women don’t.

I have absolutely no idea why women have developed such a neat knack of faking it. But let’s close the bedroom door on that one. Whatever the evolutionary reason, blokes haven’t even got off first base when it comes to conjuring up porkies.

Members of the fairer sex are almost born knowing how to be economical with the truth. They instinctively know when they grow up they are going to need to appear economical per se, especially when they realise they’ve impulse-bought a new winter coat and boots when they only went out for toothpaste and bananas.

Which is why every woman’s wardrobe has a large, dark, unwelcoming space at the bottom of it. It’s where the unexpected purchases live for a few months, until they shed their shop-new smell and can be brought out on the first winter morning with a sigh of “what do you mean, when did I buy this? I’ve had it ages”.

“Ages” is one of the most useful words in the female vocabulary.

Unless you’re a palaeontologist or a dinosaur, an age is not a scientifically approved metric-based form of measurement, but the man will understand “age” to mean a length of time greater than one or two years and kick himself for not having noticed her nice coat and boots several winters ago.

The woman, however, has a different perception of what an age constitutes. It’s hard to put a limit on it, but it’s a bit shorter than the man’s understanding, best illustrated by “we haven’t been on holiday for ages,” when he’s still suffering from the airport-lag.

Anyway, boys are not born with that same duplicity. Most of them have a good try at bending the truth or even snapping it in half, but as they swear to you that they burned their hand making a cup of tea rather than constructing home-made cigarette lighters, or they were clinching a Japanese deal till late last night rather than locked in a clinch, the tell-tale signs of lack of attention to detail and inability to control their facial features are unmissable.

The scorch marks on the kitchen cupboard. The fact that the kettle isn’t even plugged in. The long blond hair on the suit jacket shoulder. The universal lack of long blond haired Japanese people in Japan, let alone in the UK.

All these details, gentlemen, minor as they may seem to you, trip you up. So, how can you learn to lie properly? Is it just about planning ahead, developing remote control of your facial muscles and mastering some CSI-style forensic skills?

Maybe. And maybe not. To be honest, everything I’ve just told you could be absolute tosh. After all, there are some things we want to keep to ourselves.

We actually don’t mind that you’re disarmingly dishonest, as long as we can spot it. So you carry on with your joke-shop fibs and your hopeless excuses.

And we’ll carry on faking it.