Animal psychologists say dogs feel stressed and unhappy when they are embraced by their owners, because it stops them being able to run away.

In a study which analysed 250 pictures of dogs as they were being hugged, eight out of 10 animals looked visibly uncomfortable.

Experts at The Kennel Club, and Battersea Dogs & Cats Home, also agreed that owners should not treat their dogs like children, because most pets did not like to be cuddled.

The new study was carried out by Dr Stanley Coren, a canine expert and professor ofpsychology at the University of British Columbia.

He analysed images of dogs being hugged by adults and children he found on the Internet, looking for signs of stress.

At an extreme end, when a dog is especially anxious it bares its teeth or may bite, but Dr Coren said there are 'subtler indicators' that it may be uncomfortable.

Signs of stress include the dog folding its ears down, half-moon eyes or turning its head away to avoid eye contact. If the dog has its eyes closed or is licking his lips it could also be a sign of anxiety. Yawning or raising one paw is another warning sign.