A ten-minute cancer test that requires just a drop of saliva and can be taken at home is being developed by scientists.

The £15 "liquid biopsy" looks for fragments of genetic material in a tiny drop of saliva.

Currently scientists use blood tests to detect cancer, but it is not an initial test as they need to have already taken a biopsy and sequenced a tumour in order to know which genetic signature to look for.

David Wong, a professor of oncology at the University of California in Los Angeles, said: "We need less than one drop of saliva and we can turn the test around in 10 minutes."

Scientist who developed the system say early results from patients with lung cancer show the new test has "near-perfect" accuracy.

Prototype products are being built and will be tested in China and Europe this year.

Eventually it could be used to diagnose a range of different cancers, said Professor Wong, who was speaking at the annual meeting of the American Association for the Advancement of Science in Washington DC.