Britain's attempt to ramp up mass coronavirus testing has been dealt a blow after key components ordered from overseas were discovered to be contaminated with coronavirus, the Telegraph can disclose.
Laboratories across the country were on Monday warned to expect a delay after traces of the virus were detected in parts due for delivery in the coming days.
It comes as ministers and public health chiefs face growing questions over why Britain's testing capacity appears to be lagging far behind other major nations including the US and South Korea.
To accelerate production, the Government has enlisted private firms to help produce thousands of kits in the hope that mass testing will be available to the public within weeks.
One of the suppliers - the Luxembourg-based firm Eurofins - sent an email on Monday morning to government laboratories in the UK warning that a delivery of key components called "probes and primers" had been contaminated with coronavirus and would be delayed.
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The firm admitted there had been "an issue" and insisted other private providers had suffered the same problem.
Exactly how the contamination occurred is not clear, and senior health sources insisted the delay would not significantly affect the UK's testing programme.
Meanwhile, Downing St accused Public Health England of providing ministers with incorrect information on the number of coronavirus tests conducted after Michael Gove claimed that 10,000 had been completed on Sunday. Only 8278 tests were carried out in the 24 hours to 9am on Sunday morning (UK time).
The Prime Minister's spokesman was yesterday forced to clarify that Gove had been referring to the capacity available, rather than the actual number completed, which had been lower.
It came 24 hours after Gove, the Chancellor, stated the Government's target of 10,000 tests per day had been hit, with ministers now pushing for 25,000 by mid-April.
However, confusion mounted when official figures published by the Department of Health and Social Care (DHSC) revealed that just under 7000 people had been tested, significantly lower than Gove had claimed.
On Monday morning (UK time), health minister Helen Whately added to the uncertainty when she told BBC Radio 4's Today programme: "We have achieved the capacity to have 10,000 tests a day. The actual number that was tested on the day in question was I think around 7000."
To compound the issue further, PHE released the latest figures just minutes later, stating that between Friday morning and 9am on Saturday 9114 tests had been completed.
PHE also stated that "testing capacity for patient care stands at 10,949 a day", prompting questions as to whether, despite overwhelming demand, health services failed to carry out the maximum number of tests available.
Last night Whitehall sources claimed the error had occurred due to Public Health England failing to make clear to ministers the distinction between the capacity available and the number that had actually been completed.
They added that a number of people were tested more than once, thereby resulting in the disparity between the statistics. Government sources said the discrepancy was partly caused by hospitals not knowing at the start of each day how many people would need to be tested, and holding back enough capacity to ensure they did not run out of tests.
The Telegraph also understands that Matt Hancock, the Health Secretary, has also privately expressed frustration that testing may not be being carried out at full capacity and has ordered any excess tests to be used on NHS staff.
NHS England chief executive Sir Simon Stevens said roll-out of testing would begin this week after staff were sampled on Saturday and Sunday.
On March 11 the UK announced it had carried out 25,000 tests in total and was aiming for 10,000 a day — a target it has yet to reach. Ministers are hoping that a new antibody test that discovers whether a person has previously contracted the virus will be ready within weeks.