While the separation of duties principle applies here, you may be thinking that there would be other principles that can apply as well.

FORBES: Teach Your Boss To Speak Security: "Separation Of Duties"

The next security principal in our list is the Principle of Separation of Duties.

FORBES: Teach Your Boss To Speak Security: "Separation Of Duties"

Previously we discussed the Principle of Least Privilege and the Principle of Separation of Duties.

FORBES: Teach Your Boss to Speak Security: Economy of Mechanism

If we were to virtualize servers, though, the principle of separation of duties would dictate that all of the systems on a given virtual server must be of the same security sensitivity.

FORBES: Teach Your Boss To Speak Security: "Separation Of Duties"

While separation of duties does apply, the principle of economy of mechanism indicates that creating multiple virtual servers on a single host with software like VMware is creating a complex system.

FORBES: Teach Your Boss to Speak Security: Economy of Mechanism

He said Ipsa's statutory mandate was "not to support MPs" but to "have regard to the principle that we should support MPs in the execution of their parliamentary duties" - which also meant having regard to the "public interest".

BBC: MPs 'are not customers' of expenses body