THE number of people waiting for treatment in hospital has reached the highest level since devolution, according to official statistics.

Since 1999, waiting lists have risen by more than 15,000, to 112,182, and the average waiting time for patients has increased by five days, figures which provoked an angry political reaction.

Malcolm Chisholm, health minister, unveiled figures which showed the average waiting time for in-patient and day cases was 36 days in the three months ending June this year. The figure was unchanged from the quarter to March, in spite of the record levels of

funding, but in 1999 the average wait was 31 days. Published by the Scottish Executive's Information and Statistics Division (ISD), they reveal that the overall number of people on the waiting list at the end of June rose by almost 5000 from 107,557 at the end of March.

Officials also admitted that patients may have to be treated abroad or in private hospitals if the NHS were to meet its target that all patients would be seen within nine months for in-patient or day case treatment.

Shona Robison, the SNP spokeswoman on health, said the executive had failed to make any significant improvements. ''It is a sign of Labour's failure that they are having to turn to the private sector to get themselves out of a mess of their own making.''

David Davidson, health spokesman for the Scottish Tories, said: ''Despite all the promises, initiatives, glossy brochures, spin and a huge funding increase, the health service officially continues to get worse. Waiting lists are now up by almost a quarter in the lifetime of this Parliament.''

Officials said that some of the rise could be because of better collection of data.

The executive can also take some comfort from the fact that NHS Scotland met the national target of no patient waiting longer than 12 months for in-patient treatment.

Nine acute trusts and the three Island board units also achieved the executive's next target, to come into force in December, that no-one should wait more than nine months for in-patient and day case treatment. The targets do not include some patients who are unable to have operations for medical or personal reasons.

On this issue, Glasgow has much left to do: 90% of the 1177 people still waiting longer than nine months live in the North Glasgow and South Glasgow Trust areas. Managers at NHS Greater Glasgow have been told they must now report every month to show whether they will meet the nine-month waiting time target by the end of the year.

If the trusts fail to reach it, patients could be treated in the private sector, in England or abroad.

Mr Chisholm said he was aware of some ''slippage'' in Glasgow's progress.''I have spoken with management at NHS Greater Glasgow and they have assured me that they will meet the nine-month guarantee.'' He said Glasgow could be helped by use of the private sector.

Patients waiting for ortho-paedic operations face one of the biggest backlogs.

Earlier this year Mr Chisholm committed (pounds) 5m to-wards the cost of private orthopaedic operations for 600 NHS patients, on top of (pounds) 4m pledged in 2002.

Hospitals in Germany, Belgium, Poland and Greece have offered to help out the NHS.