No test for Covid is 100% accurate, but the chances of a false positive result remain low. However, what are the chances that a test will have a false negative result - that is, the individual will be infected with Covid and test negative? It is still unclear at the moment, however there is an increase in such reports.

The errors were reported by people in south-west England over the past week, where a public health official said they were aware of a "large number" of inconsistent test results. The UK Health Insurance Agency (UKHSA) said it did not believe there were any problems with any testing equipment and added that there was no evidence of a new variant.

A doctor from Gloucestershire told the BBC she had seen patients in similar situations.

"The advice is to think about your local situation, to make an individual risk assessment. "If you think there is a good chance you have Covid, even if the PCR is negative, then consider it Covid and isolate yourself," Becky Reynolds, director of public health for the Bath and North East Somerset council, told the BBC.

Experts suggest that if you test positive for Covid on an LFD test, make sure you do a PCR test afterwards. If you have symptoms of Covid, isolate yourself and have a PCR test.