Nisa has confirmed two of its non-executive directors – Harris Aslam and Raza Rehman – have left its board of directors following an investigation.

The leak came to light in September last year after a file containing the addresses, phone numbers and passwords of Nisa members was made available.

Chairman Christopher Baker said: “Nisa worked with security and forensic data experts at Kroll and EY to ensure this investigation was robust and impartial. It found that a file of members’ contact information was shared by a Nisa employee on the request of a member; both parties did not understand that this was a mistake.

“Nisa is implementing wide ranging changes to increase data security and educate both staff and members on best practice. Two member directors were involved in this. They have been reprimanded by the board and apologised for their actions.”

He added that the investigation had also looked at the circumstances of the same information being leaked to the Sunday Times and found Aslam and Rehman had “acted improperly and have left the board”.

“It is important to Nisa that members of the board share and respect Nisa’s values and behaviours,” Baker said.

Aslam was identified as a Top New Talent by The Grocer in 2013. In October last year it was incorrectly reported that the 18-year-old was vying to replace Neil Turton as CEO of Nisa. Rehman is his cousin.