Automated armed sentries that could guard nuclear reactors, or keep people out of restricted areas such as the demilitarized zone (DMZ) between North and South Korea could be among the first uses, Sir Richard said.

He said machines could replace bored 19-year-olds standing on sentry duty.

“Being 19-year-olds they think about mobile phones and sex as much as they think about the opposition,” he explained. “They get hot, they get cold, so their attention span is shorter and a machine doesn’t blink, doesn’t get hot, doesn’t get cold and just follows the rules. In a defined space like the DMZ it’s as simple as: see something move and shoot at it.”

They would also keep troops out of harm’s way.

“Why would you send a 19-year-old with a rifle into a house first to see if anything is in there if you could send a machine and there are many, many many examples in the land and maritime environments.”

But as they developed, they would also be cheaper and solve some of the West’s military manpower problems.

He said: “The temptation to have them I think will be terrific because they will be more effective, they will be cheaper, they will take people out of harm’s way and will give you bigger armed forces, so the pressure to have them will only grow.