Why politicians cannot tell fibs. Easy: body language.
A politician can never fib flawlessly because their body language will always give them away, psychologists say.
No amount of coaching or media training can co-ordinate the hand gestures and facial expressions to fully cover up what a person knows not to be true.
The bite of the lip, a movement of the eyebrow or simply where they walk on the ceremonial carpet can betray what a politician really thinks and feels.
Researchers explained how to read the signs at a science meeting in Norwich.