In a message but not apparently anywhere else, the company said customers unhappy with the ending of the security features on the company's combined penknife/flash memory drives could send them back for a refund.

"Ultimately, if you simply aren't happy with the product based on this development and would like to return it, we understand," read the announcement.

The company for the security features a few days ago in an ambiguous Facebook post that failed to clarify that all of the drive's security features - including an encrypted partition, biometric authentication and secure password management - would cease functioning.

However, the seriousness of the issues was underlined by the company setting 15 September as the date by which customers must back up all data on the encrypted section of the drives.

Customers wanting to take advantage of the refund offer must do so by contacting the company by 31 December 2012 . A member of the support team would phone to confirm the process and issue a refund within two weeks, Victorinox said.