John Lewis Christmas advert fans are warned not to befriend foxes

While they tend not to be openly aggressive, contact with humans young and old can trigger a number of illnesses such as coughes, headaches, stomach aches, skin rashes and blurred vision.

Guidance from the Royal Society for the Prevention of Cruelty to Animals (RSPCA) states: “They will learn to trust people who are not causing them harm and may appear quite bold. But this is unlikely to be a sign of aggression.

“It’s important that people do not try to hand-feed foxes or make them tame as this may encourage foxes to approach people who may not like them and take action against them.”

Children playing with and eating fox droppings are the cause of many of the illnesses and families with foxes regularly appearing in their garden are urged to quickly clean away faeces.

The RSPCA says: “The risk of children picking up this parasite from fox droppings appears to be extremely low.

“If you have any concern about these and any other potential health risks from animals, contact your doctor.”

Nor are they deemed too much danger to traditional pets such as cats and dogs.

Indeed, dogs - also among the stars of the new John Lewis ad - are considered more a threat to foxes and so foxes tend to stay away from gardens containing them.

Night-time research also suggests that fox attacks on cats are extremely rare with foxes more likely to eat cats killed by cars than to target them themselves.

But, even if you live in a built-up area of town, don’t dismiss the possibility of a fox turning up in your garden as they often use railway lines to commute from the countryside.

To report an injured or sick fox to the RSPCA, ring the 24-hour cruelty and advice line on 0300 1234999.

Watch the John Lewis video here