Sprinkling too much salt on food has long been flagged up as a dietary sin linked to a raft of health problems, from strokes to heart disease.

So health-conscious salt lovers are likely to celebrate the fact that Japanese scientists have created a guilt-free way of enjoying it – by inventing an electric fork.

The prototype fork creates a salty taste in the mouth at the press of a button, due to the release of an electrical current which stimulates the tongue.

The battery-operated fork - which can create sour and metallic as well as salty tastes - was pioneered by Hiromi Nakamura at Rekimoto Lab, Interfaculty Initiative in Information Studies at the University of Tokyo.

The device, which cost researchers only £12 (Y2,000) to make, is based on the fact that a human tongues feels salty or sour when electricity is applied to it, according to the Nikkei Technology.

The technology is likely to benefit those who are required for medical reasons to limit or eliminate salt from their diet for medical reasons, such as those suffering from hypertension.

The prototype – which is not yet designed to be waterproof - was reportedly designed for an initiative called No Salt Restaurant, which aims to hold events serving salt-free full course meals.