Wigan Borough Council has given undertakings to the Data Commissioner after the unencrypted personal details of 43,000 children and young people were lost after the theft of a laptop.

The information had been downloaded on to the laptop in breach of council policy. Although the laptop was stored in a locked office, the data on the device was not protected as the laptop was not encrypted.

The laptop was stolen on 27 January from the council’s offices but the authority only disclosed the incident, more than two months on. Other laptops were also stolen at the time.

Following the breach, Nick Hudson, director of children and young people’s services at Wigan council, said: “We have taken the step of informing the public of the borough about the theft because we believe people deserve to know what has happened.”

“Apart from the names, the data on the children is in the form of numbers and codes and there are no comments or individual case notes,” he added. The council is now investigating the theft.

Commenting on the ruling against Wigan, Sally-Anne Poole, head of enforcement at the ICO, said: “I strongly advise organisations to avoid instances where employees can download large volumes of personal information.

“This incident could have been averted if the data was simply accessed from the main council computer network. Storing large volumes of personal information on portable devices is unnecessarily risky. I am pleased that the council has taken action to guard against security breaches of this nature.”

The council will ensure that portable and mobile devices, including laptops and other portable media, are encrypted. Additional training on secure data storage, backed up by stronger enforcement procedures has been agreed with the ICO.