Equipped with artificial intelligence (AI) technology trained on millions of human faces, the EchoDepth computer is the closest thing to a mind reader I have ever come across.

By scanning muscle movement and expressions on a person’s face, it can measure 52 different emotions, from happiness to anger, amusement to boredom.

Its inventor, tech entrepreneur Jonathan Prescott, says it can even tell when someone is only pretending to be listening – a scary prospect for any employee nodding off in a Zoom meeting. Perhaps scarier still, however, is its potential on a battlefield.

For Prescott is talking to me – and yes, I’m listening – at this week’s Defence and Security Equipment International, or DSEI, the UK government-backed arms fair held every two years at London’s Excel Centre.

In wars of the future, technology such as this could be installed on smart glasses in a soldier’s helmet – allowing them to tell whether those around them are friendly or hostile, full of fight or on their last legs.

“The model has been trained on images of people in different emotional states, which compare biometrics of facial muscle groups and things like gait analysis,” he explains.

“These all change depending on whether people are confident, traumatised, or intent on posing a threat.”