The eyes have it for a lying President

The quest to develop a foolproof lie detector may have flummoxed scientists.

But body language experts say there is no need for fancy equipment to spot a fibber. Research involving criminals suggests there are dozens of simple giveaways.

A key sign is how rapidly the person blinks - with 20 blinks a minute considered the norm. Experts analysing video footage of former US President Bill Clinton denying his infidelity with Monica Lewinsky found he blinked at three times the normal rate.

Signs of deception were also evident in his hands, which he clasped together, symbolising the extent to which he was trying to conceal his thoughts.

Covering, or partially covering, the mouth, is also said to be a sign. Another key "distress" signal is known as an oxbow mouth when the lower lip is pressed into the top lip.