﻿Police and intelligence agencies around the world have, for almost 100 years, relied on lie detectors to help convict criminals or unearth spies and traitors. 
The polygraph is beloved of the movies, with countless dramatic moments showing the guilty sweating profusely as they are hooked up. 
But the invention could soon be defunct. Researchers in Britain and the Netherlands have made a breakthrough, developing a method with a success rate in tests of over 70% that could be in use in police stations around the world within a decade. Rather than relying on facial tics, talking too much or waving of arms – all seen as tell-tale signs of lying – the new method involves monitoring full-body motions to provide an indicator of signs of guilty feelings. 
The polygraph is widely used in the US in criminal and other cases and for security clearance for the FBI and CIA but is much less popular in Europe. There has been a lot of scepticism in the scientific and legal communities about its reliability. By contrast, the new method developed by the researchers has performed well in experiments. 
The basic premise is that liars fidget more and so the use of an all-body motion suit – the kind used in films to create computer-generated characters – will pick this up. The suit contains 17 sensors that register movement up to 120 times per second in three dimensions for 23 joints.