“The investigation by the HPA was to ensure that there wasn’t an ongoing risk and we were satisfied that Pontin’s took all appropriate measures to avoid risk of infection.”

The disease is usually contracted by inhaling water vapour from sources such as whirlpool baths, showers and cooling towers.

Bacteria which causes the disease is common in many water sources, but only becomes a problem when temperatures allow rapid multiplication of the bug. In serious cases, it causes pneumonia while less serious cases suffer flu-like symptoms.

The camp completed a deep clean on all water systems as a precaution when they were notified of the woman’s condition and isolated the block of apartments she had stayed in.

The HPA said there were 359 cases of Legionella pneumonia in England and Wales in 2008, nearly half of which were associated with travel, both in the United Kingdom and abroad. About ten per cent of those affected died.