The UK is currently projected to have one of the worst infection and death rates of any country in Europe.

The NIS document seen by openDemocracy is authorised by Dr Susan Hopkins, Professor Maria Zambon and Professor Andrew Mumford: all senior research directors who report to the chief executive of Public Health England, Duncan Selbie, and ultimately to Matt Hancock as Health Secretary.

UK ‘bottom of the queue’ for reliable tests

Evidence of “quality assurance difficulties” for key reagents – essentially the test’s chemical makeup – is quoted in the document as one of the contributing factors for the test’s unreliable performance.

The document says that Public Health England (PHE) has reviewed its own COVID-19 test and has agreed “immediate actions” to mitigate or rectify the problems. Among the advice given to laboratories using the PHE test is to be careful before “calling” a result negative, to "retest ambiguous samples", and to move towards using commercial tests.

Private-sector tests are sold by major pharmaceutical firms such as Hoffmann-La Roche, Abbott Laboratories and others. Commercial laboratories and academic institutions, such as the Crick Institute in London, largely use commercially available tests and not the PHE test.

However due to the worldwide demand for COVID-19 testing, these commercially available tests are now in short supply. If all NHS labs were to suddenly be mandated to switch to commercial products, one leading professor said: “We would find ourselves simply at the bottom of a very large queue for these critical materials.”

The three advisers who authorised the document make it clear that use of the flawed PHE test cannot continue.

But, given the lack of an immediate alternative, they advise NHS labs in the meantime to take care in interpreting the results.

A “shortage of swabs” and the specialist fluid used to “transport” the swabs to laboratories are also identified in the documents as causing variations in the performance of the Public Health England SARS test in NHS laboratories.

The importance of accuracy in test results was emphasised late last month by Professor Chris Whitty, the government’s chief medical officer. At a time when questions about the reliability of the PHE test would have been surfacing internally, Professor Whitty discussed the use of tests that might detect the presence of antibodies in those who had recovered from the virus.

He said tests needed to be “incredibly accurate,” adding: “If they are not accurate, we will not release any of them.”

Last month Health Secretary Matt Hancock authorised the purchase of £20m antibody tests from China. The tests were later found to be unreliable and effectively junked. It is understood the Chinese tests were 60 percent reliable.

You can read the full leaked document here