There are huge variations in the cost of hospital food which are unrelated to quality or to whether services are provided in-house or by contractors, according to an Audit Commission investigation into hospital catering.

Though the review found patient satisfaction with hospital meals to be quite high - with an average satisfaction score of 7.6 out of 10 - a report of the findings says: 'Patient satisfaction [as currently measured] shows no relationship to the cost of providing a catering service.'

The starkest finding was that net expenditure per patient per day ranged from£2.80 to£20. 'Some of this will be due to the level of income generated from nonpatient services and the trust's pricing policies, ' the report says.

But it adds that 'the only factor to be significant' in explaining the variation was trust size. 'There is no association between the net cost of catering and whether the service is provided externally or in-house, or with the type of cooking method used, ' the report says.

Hospital Caterers Association chair Pam Miller said the wide variation found by the Audit Commission reflected the fact that 'they're using net costs, taking into account any income generated'.

But the Audit Commission also found that trusts are not always able to cover the costs of providing food for staff or visitors. Only 35 per cent of trusts surveyed monitored the actual contribution or subsidy from non-patient food, while 'even fewer have established an appropriate level of subsidy and set a target'.

The average subsidy was about£153,000 a year - 'equivalent to an additional 84p that could be spent daily on food or beverages for each patient', the report says.

Ms Miller said offering subsidised staff meals was a way to meet the human resources agenda, improving working lives and implementing the New Deal for junior doctors, as well as 'helping with retention issues'. The government responded to the report by announcing a better hospital food panel, including patients, to be led by TV personality Loyd Grossman.

Acute Hospital Portfolio: catering.Audit Commission Publications.0800-502 030.£10.