Sleeping pills seldom worked for 40 percent of the poppers who suffer from insomnia, says a survey of 20,000 people, according to a British study.

Some 42 percent of the patients currently on medication have been sleeping badly for over 11 years or more. A further 22 percent had insomnia lasting two to five years, while one in six had suffered between six and 10 years, the survey revealed.

Experts said the study suggested that sleeping pills were not combating long-term sleep problems and that cognitive behavioural therapy has been proven to be more effective.

Around 10 million National Heath Service (MHS) prescriptions for sleeping pills are issued each year. But NHS guidelines say they should be for short-term use only - usually for two weeks and up to a maximum of four weeks at a time.

Findings from The Great British Sleep Survey of more than 20,000 adults in Britain found we are a nation of poor sleepers. The average score of sleep quality was only five out of 10. Long-term poor sleepers were twice as likely to have relationship problems, suffer from daytime fatigue and lack of concentration.

The survey also showed almost one in 10 with insomnia were on sleeping pills prescribed by their doctor, with one in five using over the counter remedies. American research this year found sleeping pills may significantly increase the risk of premature death.

The latest survey was sponsored by Sleepio, an online sleep improvement programme which uses cognitive behavioural techniques. Andrew McCulloch, chief executive of the Mental Health Foundation, has campaigned for the NHS to highlight the importance of sleep.