A blood test for more than 50 types of cancer has shown real promise in a major NHS trial, researchers say.

Scientists say they are excited by the results of the study led by Oxford University which showed the test was able to correctly identify two-thirds of cancers among 5,000 people who went to their GPs with suspected symptoms.

The Galleri test remains very much a "work in progress", the researchers, from Oxford University, say, but could increase the number of cancers identified.

A positive test meant the patient was likely to have cancer. Tumours were confirmed 75 per cent of the time.

A negative test meant cancer was unlikely but could not be ruled out completely.

Although not accurate enough to "rule in or rule out cancer", the test was really useful for patients lead researcher Prof Mark Middleton told BBC News.

"The test was 85% accurate in detecting the source of the cancer - and that can be really helpful because so many times it is not immediately obvious when you have got the patient in front of you what test is needed to see whether their symptoms are down to cancer," he said.

"With that prediction from the test, we can decide whether to order a scope or a scan and make sure we are giving the right test the first time."

The findings will be presented at the American Society of Clinical Oncology conference, in Chicago, and published in The Lancet Oncology journal.