Teenagers in Britain are turning into a "junk sleep" generation, according to a new report published today.

Playing computer games and watching television is preventing youngsters from getting enough sleep to maintain good health, found the Sleep Council.

And, with nearly one in three teenagers surviving on as little as four hours sleep per night, many are going to school exhausted.

Commenting on the report, Dr Chris Idzikowski, from the Edinburgh Sleep Centre, said: "This is an incredibly worrying trend. What we are seeing is the emergence of junk sleep - sleep that is of neither the length nor quality that it should be in order to feed the brain with the rest it needs to perform properly at school."