A security breach at the UK's Essex County Council has exposed personal data on 400 people.

"Names, addresses and financial information about people in 'substantial' and 'critical' need of care were sent from the Adults Health and Community Wellbeing Department to a computer outside of County Hall," The Essex Chronicle reports. "A council staff member was sacked following the breach, which was reported to Essex Police and the Government's Information Commissioner."

"The council said in a statement that it was unable to give any 'specific details' of the alleged breach," PublicService.co.uk reports. "But it confirmed an investigation was now underway focussing on an ex-employee who was said to have breached information security policy. 'We are taking this extremely seriously and have informed the police and the Information Commissioners Office,' the council's statement read. 'Whilst the ex-employee had signed a declaration stating they had deleted the information and not shared it with anyone, it is our duty to inform service users that their information has been compromised.'"