GERM expert Professor Hugh Pennington has called for a public inquiry into the outbreak of Legionnaires' disease, saying something had gone "badly wrong".

The distinguished microbiologist said lessons must be learned to prevent a repeat of the Edinburgh outbreak, in which three people died.

He described the illness as one of the most serious that can be caught in Britain, but said it was preventable.

Mr Pennington said: "We have known how to prevent it for years and years, but it seems we are not as on top of it as we should be.

"The bug is not going to go away. We are never going to eradicate it, but we can prevent infection by paying attention to things like cooling tower maintenance, making sure they are treated with the appropriate chemicals."

Work is still ongoing to identify the source of the infection in Edinburgh and the public has already been warned it may never be confirmed.

A cluster of cooling towers in the east of the city have been the focus of much of the attention.

Mr Pennington expressed concerns about how often cooling towers are inspected by regulators.

He said: "There is an issue there. I think what a public inquiry could do is to look at all that.

"It is not just the circumstances of a particular outbreak that a public inquiry looks at, it also looks at the general background."

Mr Pennington chaired the public inquiry into the E.coli outbreak in Wishaw, North Lanarkshire, in 1996, which led to new legislation, and another inquiry into an E.coli outbreak in Wales in 2005.

He admitted inquiries were expensive but said governments tended to take notice of the findings and act on them.

Jackie Baillie, health spokeswoman for Scottish Labour, said: "Professor Pennington's intervention is significant and his authoritative voice should be a reason for the Scottish Government to pause and reflect on their decision not to have an independent inquiry into this outbreak.

"There are real fears the inspection regimes the Health and Safety Executive and local authorities have are inadequate and are failing to protect citizens from these fatal outbreaks.

"Scots deserve to know lessons will be learned and every step taken to prevent another outbreak and those who have suffered and lost relatives deserve nothing less."

Patrick McGuire, partner at Thompsons Solicitors who are representing some of the victims, welcomed Mr Pennington's call.

He said: "I am delighted Professor Pennington has added his voice to the calls for a full, independent public inquiry into this outbreak.

"Although many factors could have lead to the outbreak of Legionnaires' disease in Edinburgh, mismanagement and human error lie at the very heart of the matter.

"The victims of this outbreak – including not just those with Legionnaires' disease, but also those with Pontiac fever and other related illnesses – demand answers and the assurance that this can never happen again."

The total number of confirmed and suspected cases of Legionnaires' disease from the Edinburgh outbreak is 101. Health officials have declared it is over. There have since been further deaths from Legionnaires' disease in Stoke-on-Trent, linked to a hot tub.

A spokesman for the Scottish Government said: "It would be entirely inappropriate to comment on a public inquiry at this time. The Health and Safety Executive is continuing its enquiries and any consideration of a public inquiry would have to wait until their investigations are complete."