REMEMBER Norah the nit nurse?

She used to attend school every so often and go through children’s hair with a steel comb looking for wildlife.

If she was still active today, she’d be busy. We may live in a relatively clean age, where shampoo is available in every household, but Ian Burgess, director of the Medical Entomology Centre, says that between eight and 15 per cent of the school population have nits at any one time.

Head lice are prevalent among children because they are passed on by head to head contact.

They can also be passed on to their parents, the same way, so watch out – adults are not immune.

Experts say the best way to get rid of them is to comb through the hair when it is wet, when the lice are most vulnerable.

And parents shouldn’t get traumatised about discovering nits on their children – they are normal, but they do need treating.

When my wife found nits in the hair of our daughter Sian, when she was about six, she didn’t want her to get upset. Fat chance.

“Ooh,” said Sian in wonder, not at all perturbed. “Does that mean I’ve got my own pets?”

Yes, but not for very long.