A Star Trek-type medical tricorder, diagnosing medical problems at the push of a button, could be a step closer to reality.

Researchers at Birmingham's Aston University have developed a working desktop prototype of a machine that can take readings from blood and human tissue using laser beams.

It has been successfully trialled at a hospital in Scotland, while a portable prototype is being worked on.

Developers at the Aston Institute of Photonic Technologies said it allows a range of tests to be carried out "quickly and painlessly."

The innovation means the once fanciful idea - depicted in sci-fi show Star Trek - of doctors using tricorders to effortlessly diagnose a variety of ailments may soon become reality.

The machine uses three separate lasers to monitor how effectively blood is delivered to tissue, measure blood-oxygen levels and look at cell metabolism.

It works by shining the laser beam on the patient's skin, while the patient feels nothing.

That data is then instantly processed by a computer, and re-produced as a graph.

The device has already had practical applications, being used in diagnostic procedures for strokes and skin cancers, and is non-invasive, as no needles are necessary.

It can constantly monitor blood delivery above the eyebrows, helping doctors mitigate the risk of stroke in patients with hypertension.

In cancer patients, researchers have said it is a high-precision way of identifying the margins of head and neck skin cancers, which could help reduce the risk of tumours returning.

A prototype wearable monitor has been developed that athletes can wear on their wrists. Much of the technology is ready to go into production.

Professor Edik Rafailov, of AIPT, said: "This technology will allow a range of tests to be taken quickly, painlessly and without any reason for patients to feel nervous - there are no needles involved.

"Results are instantaneous, which is better for patients and more efficient for healthcare providers."

His colleague and senior research fellow, Dr Sergei Sokolovsky, said: "We have managed to bring together multiple technologies in a machine that is compact, simple to use and - from a patient's perspective - extremely user-friendly.

"It is a huge step forward in terms of improving the speed of diagnostic work and also in terms of reducing invasive tests."