Professor Lamine Mahdjoubi from the University of the West of England says children are choosing not to use play areas because they are too safe.

He is calling on fellow designers to produce challenging play environments.

"It is essential designers get it right if future generations are to exercise and play outside," he said.

"Children lead more sedentary lives chained to video games and ogling the box rather than exercising their limbs and learning how to tackle risks leading in some cases to health problems like obesity," said Prof Mahdjoubi.

"In addition to this, streets are rarely used for play because of risk of traffic accidents, the fear of child abduction from paedophiles or violence and intimidation from older children and exposure to drugs culture," he said.

The professor has organised workshops for experts involved in child health care as well as architects, designers, landscape designers and local council representatives to look at what can be done to encourage them to exercise outdoors.