Accident and emergency waiting times across England and Wales are continuing to get longer - and the blame may lie with hospital management as much as inadequate resources, according to the findings of a national review by the Audit Commission.

Despite the NHS plan pledge to improve trolley waits, the commission found that the percentage of patients admitted within four hours dropped from 89 per cent in 1996 to 76 per cent in 2000.

Whereas 72 per cent of patients saw a doctor within an hour five years ago, last year it was 53 per cent.

But worryingly for ministers and managers, there is little evidence to explain why the situation is deteriorating. 'The available data can support a particular cause of long waits in some departments (for example, too few cubicles for examining patients or a shortage of doctors or nurses), ' the report says. 'But in the majority of cases, no cause is discernible.

'This suggests that waiting times are determined by a host of organisational and managerial differences as much as by resources and staff levels.'

The report claims that the performance of trusts varies widely across the NHS - with longer waits found more frequently in London and in larger A&E departments.

Again, the reasons are not clear - the types of patient treated may be one, the availability of primary care services another - though departments with fewer than 40,000 patients a year all managed to have 50 per cent of their patients seen by a doctor within an hour.

The commission also found that staff workloads vary 'very widely' across departments, suggesting managers are not allocating staff to tasks to which they are suited.

'About 60 per cent of patients are classified as non-urgent and a high proportion of these could be treated by nurse practitioners.

However, only a tiny proportion of departments (5 per cent) make any significant use of them.

Hospital managers should address these anomalies, ' it says.

Significantly, it says that although workload pressures on nurses have probably risen in recent years, again there is wide variation between departments.

Nurses can see as few as 1,000 patients a year, to more than 2,000, depending on where they work.

But the report adds: 'There is no evidence that those departments that are relatively short-staffed have longer waiting times than those which are relatively generously staffed.' It also attacks the poverty of management information.Twentynine departments (14 per cent) still had no A&E computer systems - they could only supply the commission with data on waiting times by trawling through patient record cards by hand.

The report concludes that 'it requires much management effort and skill... to bring about improvements in capacity, efficiency and quality.'