Is your beard hiding a dirty little secret?

Previously clean-shaven pillars of society have suddenly sprouted facial hair where it had been unthinkable before.

George Clooney has rocked the hirsute look before, but he’s gone back to his beard with a vengeance and, it has to be said, he looks great with his pepper ’n’ salt number.

That’s what I reckoned I looked like when I grew a beard at the end of last year (more salt than pepper, it has to be said) but Mrs S wasn’t convinced.

She said it added years to me and was delighted when it came off on Boxing Day.

Graham Norton, however, seems quite content to carry on with the sort of fluffy grey beard usually only seen on close-to-retirement geography teachers.

Even clean-cut Match Of The Day maestro Gary Lineker has gone the beardy route but, typically, not the whole hog, contenting himself with a neat and tidy silver goatee.

Prince Harry, for heaven’s sake, even managed to make ginger beards look good, though his big brother’s beard didn’t last long.

Either Kate insisted it came off, or he got fed up of Prince George tugging it.

Mind you, the less said about Simon Cowell’s calamitous stubble, the better.

But there’s one big beard brainteaser over and above the whole “does it suit you?” question — are they unhygienic?

Over recent years, there have been contradictory headlines about the supposed hygiene aspects of facial hair.

Some have claimed that they are thronging with bacteria, including those from human faeces.

But were people just being influenced by classic cartoon depictions of beards that often showed stray bits of food caught up in the bushy whiskers?

Infectious disease specialist Dr Chris van Tulleken decided to get to the bottom of the matter by doing his own, proper, sampling.

Chris swabbed the beards of men on the street in London and delivered the samples to Dr Adam Roberts of University College London, who cultured them and then identified the species.

He found over 100 different bacteria from 20 different beards, plus some moulds.

However, when he identified the bacteria, they were all commonly found on skin and were mostly of the standard Staphylococcus species.

There was one — Barnesiella — which can be found in the small intestine, but that doesn’t necessarily mean it came from poo.

So, it appears that beards are not likely to be unhygienic and are not harbouring particularly nasty bacteria.

However, Adam also tested the bacteria for their antibiotic properties — how well they killed other bacteria.

In an environment like a beard, some bacteria have evolved to produce toxins to kill others and these toxins are what we use as antibiotics.

Adam found one species of bacterium in a beard swab that created a “ring of death” around it, killing other bacteria and he will investigate this further as new antibiotics are vital in medicine.