Thousands of council staff may have been put at risk of fraud after a laptop containing their addresses and financial details was stolen.
The laptop, containing personal information of Worcestershire County Council staff was stolen in a street robbery last week.
Staff were informed of the theft by letter on Friday.
A spokesman said the council's first priority was to protect staff's confidentiality and to protect them.
One staff member told BBC News he was horrified such a mistake had been allowed to occur.
The letter he received said: "The personal details include names and addresses.
"Other details relating to National Insurance and Bank Accounts are also held on the computer but are not so easily deciphered.
"Although the theft appears random rather than planned and the computer is password protected there is nevertheless a risk that this information might be misused."
Staff were also unhappy the theft occurred some days ago but they had only just been told.
In a statement Patrick Birch, the council's director of corporate services, said the laptop was owned by Serco Solutions, one of its IT suppliers.