There have been a string of lost data incidents in recent months
Discs containing personal information on almost 18,000 NHS staff have gone missing from a north London hospital.
Whittington Hospital NHS Trust admitted the discs were lost when they were put in the post by mistake in late July.
The discs contain names, addresses, dates of birth and National Insurance numbers, of 17,990 staff members.
In a statement, the hospital said the four discs were password protected and did not contain bank account details. An investigation is under way.
The trust said police had been informed, but advised that the incident should be treated as a loss with minimal risk to staff.
David Sloman, Chief Executive of the Whittington Hospital NHS Trust, said the hospital had apologised to all the staff involved and one staff member had been suspended.
"It is trust policy to send any such information by courier. To our knowledge this is the one and only time that such information was directed through the post," he said in a statement.
Those affected include current staff and some former staff at the Whittington Hospital, Islington Primary Care Trust, Camden Primary Care Trust and Camden and Islington NHS Foundation Trust.