The device has been designed to help doctors track medical tools, known as endoscopes, during internal examinations.

Until now, medics have had to rely on expensive scans, such as X-rays, to trace their progress.

The new camera works by detecting light sources inside the body, such as the illuminated tip of the endoscope's long flexible tube.

Prof Kev Dhaliwal, of the University of Edinburgh, said: "It has immense potential for diverse applications, such as the one described in this work.Early tests have shown the prototype device can track a point light source through 20cm of tissue under normal conditions.

The new camera can detect individual particles, called photons, and is so sensitive it can catch tiny traces of light passing through tissue.