Max Pfeiffer, at the University of Hannover, believes the invention will allow tourists to navigate unfamiliar cities without taking their eyes off the sights, because they no longer need to follow directions.

When the muscle contracts it pulls the leg out and away from the body, turning the walker either right or left depending which leg has been targeted. The contraction happens on the upswing, and feels like a gentle tug in one direction. Apparently it does not hurt, although some noticed a strange tingling sensation..

The device has been shown to work on students who were successfully steered through a park in Hannover by researchers using a mobile phone to send Bluetooth signals to the electrodes.

In future, the researchers hope to hook up the device to GPS so that a destination could be programmed in.

As well as benefiting tourists, Mr Pfeiffer said it could be used in sports, crowd control, or to direct firefighters in burning buildings.

Student volunteers who tested the system said the tiny electric currents caused the change in direction to happen subconsciously, without affecting how you walk.