The security guidance published by the UK government’s National Technical Authority for Information Assurance (CESG), is applicable to devices running Enterprise versions of Windows 7 and Windows 8, acting as client operating systems, which include BitLocker Drive Encryption, AppLocker and Windows VPN features. The UK government’s National Technical Authority for Information Assurance (CESG) advises organisations on how to protect their information and information systems against today’s threats.
The Windows 8 Secure Boot process alerts a user when an attempt to subvert the security controls has taken place. It is important that users know how to identify and respond to this alert.
Read more here – https://www.gov.uk/government/publications/end-user-devices-security-guidance-windows-7-and-windows-8/end-user-devices-security-guidance-windows-7-and-windows-8