Help is available for people who are overcome with nerves when faced with the age-old custom of shaking hands. British scientists unveiled a step-by-step guide to the perfect handshake.

Researchers at the University of Manchester, in northwest England, found that the biggest problems were sweaty palms, limp wrists, gripping too hard and lack of eye contact.

Geoffrey Beattie, the university's head of psychological sciences, came up with a mathematical formula which took into account 12 key measures needed to convey trust and respect to the recipient.

They include vigour, eye contact and hand temperature.

"The human handshake is one of the most crucial elements of impression formation and is used as a source of information for making a judgment about another person," he said.

The researcher added he was surprised "that up until now there has not been a guide showing people how they should shake hands," which has been a traditional greeting and a key part of business deals for thousands of years.

Prof Beattie's steps to the perfect handshake, for both men and women, are: use the right hand; a complete grip and a firm squeeze (but not too strong); a cool and dry palm; approximately three shakes, with a medium level of vigour, held for no longer than two to three seconds.

The handshake must also be executed with eye contact kept throughout and a good natural smile with an appropriate verbal statement, according to the scientist.