The personal information of 1.6 million people has been put at risk after a CD was sent to a landfill site by an NHS trust by mistake, a watchdog said.
The Eastern and Coastal Kent Primary Care Trust put the CD, which contained the name, address, date of birth, NHS number and GP of about 1.6 million people, in a filing cabinet during an office move.
But no one told staff who sent the cabinet to the landfill site and it has not been recovered, the Information Commissioner's Office said.
The trust said it would now take action to bring in clear policies and procedures for when moving office, improve staff training and boost security against unauthorised and unlawful processing, accidental loss, destruction and damage of personal records.
An undertaking signed by the trust's chief executive, Ann Sutton, read: "The Information Commissioner was provided with a report by the data controller informing that a filing cabinet containing personal data had been sent to landfill during a move of office premises.
"The filing cabinet contained a CD holding the address, date of birth, NHS number and GP practice code of approximately 1.6 million individuals. When planning the office move the security of the CD was considered and it was deemed appropriate to store it in the filing cabinet concerned.
"Although communication was established with the project manager co-ordinating the move, the existence of the CD was not communicated leading to the disposal of the filing cabinet.
"It was also found that the team concerned were not up to date with their information governance training and had not accessed relevant guidance on how to dispose of the CD.
"The data controller did take steps to attempt to retrieve the filing cabinet once discovered missing, however the cabinet had already gone to landfill and was unable to be recovered.
"It has been noted that the data controller has taken substantial remedial measures to prevent the reoccurrence of such an incident."