Commuters obsessively scrub their hands with gel. Hand sanitisers are artfully placed on office desks. In Welwyn and Hatfield, borough councillors have been issued with antibacterial handwash. But is this really better than the humble bar of soap at protecting against swine flu?

Soap and water is just as effective as an alcohol-based hand gel at repelling viruses, according to Professor Ron Eccles of the Common Cold Centre at Cardiff University. Chris Smith, a clinical lecturer in virology at Cambridge University who broadcasts as “the Naked Scientist”, agrees. “They are both equally good if used correctly and regularly,” he says. “Soap smells nice but then if you are a chronic fingernail biter or nose-picker it could be advantageous to use a gel because they taste absolutely disgusting.”

Manufacturers make the gels taste foul so people won’t drink them for their alcohol content. The alcohol works by deactivating the flu virus by attacking the oily layer, or envelope, around it. Soap and water does this too, and is actually preferable to gels for tackling the norovirus, the vomiting bug, which is insensitive to alcohol.

The problem with both is that after disinfecting your hands you only need to touch an infected surface to pick up the virus again. Better, says Eccles, is a protective foam with acidic properties, such as Vicks First Defence, which maintains an acid environment on the skin for several hours.

Ultimately, however, a flu particle measures just 1/10,000mm. “They bob around on air currents,” says Smith. “Breathe in a handful of particles and you get infected. There is only so much you can do with washing your hands.”