Train companies have been criticised for covering up the discovery of a potentially lethal bug found on trains running across Britain.
Tests that started last month on trains of most of Britain's 20 operators, including ScotRail, have revealed one in three tested positive for legionella, the bacteria that causes the potentially fatal pneumonia, Legionnaires disease.
An internal e-mail sent to all train firms in the UK from the Association of Train Operating Companies, and leaked to our sister paper The Herald, says it was found in toilet systems.
Train firms and health experts are unable to say whether the bug has been behind any cases of Legionnaires disease, which is transmitted by infected water droplets.
There have been three known deaths in Scotland in recent weeks and experts have had major problems detecting the cause.
A number of train companies, including ScotRail, have undertaken a one-off disinfecting of carriages in advance of more detailed guidance on how to deal with the risk.
ScotRail said two traces of legionella were found after sampling 15 toilet water tanks.
A ScotRail spokesman said: Both were chlorinated and the bacteria eradicated.
The e-mail from Peter Lovegrove, operational resilience manager of ATOC, was sent on Wednesday and says the group will not be proactively contacting the media or otherwise publicising the position .
He adds: No-one is suggesting there is a significant health risk, this is about reputational risk .
A spokesman for Railfuture, the independent campaign group for improved rail services, said: They should be as open as possible about this.
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