Nearly 20,000 cases of pest infestations in NHS hospitals have been recorded over the past two years, the Conservatives have said.

Mice, rats, squirrels, bedbugs, fleas, cockroaches, ants, flies, silverfish and even foxes have all been reported by hospitals responding to Conservative freedom of information requests.

Responses from 127 trusts show that 70 per cent had to call out pest controllers 50 or more times between January 2006 and March 2008.

Examples include maggots found in patients’ slippers; rats in a maternity unit; wards “overrun” with ants; mice “all over” wards; cockroaches in a urology unit; fleas in a neonatal unit; and a store for sterile materials infested with mice.

Andrew Lansley, the Shadow Health Secretary, said: “Labour have said over and over again that they will improve cleanliness in our hospitals but these figures clearly show that they are failing.

“It is difficult for health service estates to maintain a completely pest free environment but the level and variety of these infestations is concerning.

“We need greater transparency in NHS infection control, and publishing data like this is one way in which we can drive up overall hygiene standards."

The data does not show whether infestations are increasing or diminishing, nor does it show that, unpleasant as they may appear, the pests found in hospitals have any clear implications for the health of the patients.

Few households can claim to be free of ants, mice, or silverfish all the time, and rats are never far away. Given the scale of the NHS, the size of its buildings, and the constant flow of patients in and out, the levels of infestation do not appear remarkable.

Malcolm Padley, a spokesman for Rentokil, which provides pest control for hospitals nationwide, said: “Pests are attracted to most buildings whether they are in the private or public sector. You are likely to see pests at some point in some form or another.

“There is a problem with large buildings, like hospitals, in particular and many buildings with a lot of grounds are also attacked.

“We have definitely seen an increase in the number of call-outs about bed bugs and rodents nationally. A lot of people could be going into hospitals with bed bugs on their clothing.

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