Basildon Council staff personal data published online
Details of an Essex council's entire workforce were released online in a "serious security breach", it has said.
Names, dates of birth, sickness information and work contact numbers for Basildon Council's staff of "about 1,000" were published on the internet.
A council worker spotted the breach on Monday and the details were removed by Tuesday, the council said.
The council believes data held by a contractor was put out by a third party. Police are investigating.
The authority said the breach is believed to have been one of several within the private and public sector and that it had advised staff to report suspicious or unusual phone calls.
'Discovered by chance'
Head of corporate services Dawn French said: "This is an extremely serious situation and one which we acted to rectify as soon as it came to our attention.
"I can say that by working urgently and closely with relevant organisations our officers have now managed to ensure that the details of all of our staff are no longer available on the web.
"The information was discovered online by chance by one of our staff and as soon as it was brought to our attention we immediately set about removing it as quickly as possible.
"We are not aware of whether the information was accessed whilst it was available on the internet but we also do not have any specific information to suggest that staff will be affected as a result of this.
"However, we have suggested to staff that they take precautionary measures in relation to any calls or other contact which is unusual or suspicious and to report anything of concern their manager."
She said that staff would be "understandably concerned" and could get advice and support if necessary.
The Unite union's national officer for local government Peter Allenson said: "The more that local government services are outsourced to private contractors, the greater the chances of these abuses occurring.
"This is a dangerous development that needs to be seriously considered by councils across the UK.
"Confidential information about staff needs to remain exactly that - confidential."