£1.3m patients facing penalty for 'no shows'

Now, under Government plans to penalise "no-shows", one in seven people face being pushed to the back of the queue for treatment.

The worst-hit boroughs are likely to be Tower Hamlets, Lambeth, Southwark and Ealing, where up to 70,000 people a year miss outpatient clinics.

Each missed appointment costs £100, bringing the total wasted across the NHS to more than half a billion pounds and in London, where the problem is worst, to more than £134million.

Gordon Brown has called for timewasters to be punished by having to wait longer for treatment. He said people who do not turn up should lose the right to be seen within the key target time of 18 weeks. It is part of a drive to improve patient "responsibilities" in the NHS.

Now the scale of the move can be revealed as figures compiled for the Evening Standard by the NHS Information Centre show that at least 1.35 million hospital appointments are wasted every year. An average of 12 per cent of all outpatient appointments in the capital are missed and in Lambeth the figure is more than one in five.

Dr Jonathan Fielden of the British Medical Association, said: "This causes huge disruption for patients and hospital staff.

"Patients need to have more respect for the service but the NHS also needs to work harder to make appointments more convenient and flexible."

Health service insiders say hospitals do not make it easy enough for people to change or cancel appointments. A computer booking system was supposed to reduce the problem but the number of missed dates still rose six per cent between 2005 and 2006.

Doctors said a side effect of the plan would be to help the Government hit its 18-week targets. By December all patients have to be treated within that time yet one in 10 is still waiting a year. If large numbers lose the guarantee of care within 18 weeks it would make the figures look better.

Other experts called on the Prime Minister not to target patients unfairly. Nigel Edwards of the NHS Confederation, which represents health trusts, said: "It cannot be a blanket plan... there are many legitimate reasons why people miss appointments."

Lambeth Primary Care Trust said: "It is not that the people of Lambeth can't be bothered - a quarter of the population moves around in any one year and can find it difficult with transport."

The Department of Health said it was trying to encourage patients to use the NHS "sensibly and responsibly" and was asking trusts to send text message reminders to people, making it easier for them to cancel appointments.