Wearing underwear on the outside of your clothes can turn a tedious trip to the store into an amusement park romp

Is giggling better than a light box to banish those winter blues? America is full of laughter therapists who claim that “humour helps healing” but we sneery, cynical Brits have been slow to catch on.

However, evidence for the health benefits of laughter is mounting. It lowers the blood pressure, reduces the level of stress hormones, boosts the immune system, increases muscle tone and encourages the release of endorphins, the body’s natural feel-good opiates.

Laughter also increases the level of oxygen in your blood, gives your heart and lungs a good workout and improves the blood supply to your skin. And, as with sex, the relaxation phase after a hearty laugh is great for insomnia (especially for men).

What’s more, if you’re happy and optimistic, you’re likely to have more lovers and lots of friends - and you’re less likely to get sick.

On the other hand, if you’re unhappy and worried, you’re at increased risk of all sorts of illnesses - from flu to depression and cancer. And when happy people do get ill, they tend to get better treatment than miserable sods, because the doctors and nurses enjoy treating people who smile more.

Of course, teachers can’t be shiny, happy people all the time and some seem to thrive on being grumpy. Most of us learn how to be happy and enjoy life as children and then lose it as we get ground down by responsibility.

I only realised this when I had kids. My son farts like a trooper and wears his pants on his head. My wife thinks it’s all very childish but I laugh like a drain. As Dr Patch Adams, the American king of laughter therapy, puts it: “Wearing underwear on the outside of your clothes can turn a tedious trip to the store for a forgotten carton of milk into an amusement-park romp”.

I’m not sure the magistrate would see it like that, mind. Patch believes reserved people are never funny and that you have to take a few risks to get laughter.

He once turned up to a hospice dressed as the Grim Reaper with the sign “forthcoming attraction” pinned to his front.

You may not find that in the least bit amusing, but when did you last really laugh? Not just a titter but an uncontrollable belly laugh? You know, when you shook so much you thought your pants would never dry?

Last time I asked a group of patients, one man admitted not having laughed out loud for 10 years. What sort of a life is that?

So I took him off his tablets and prescribed “fun” instead, three times a day, avoiding milky drinks.

Off he went and gave it a go and all his irritating little aches and pains disappeared - until he was arrested for peeing in the fire bucket at Nailsea station. Still, you’ve got to laugh

Dr Phil Hammond is a GP and chair of governors at a primary school in Somerset