The government has quietly removed 1.3m coronavirus tests from its data because of double counting, raising fresh questions about the accuracy of the testing figures, The Guardian reports.

In the government’s daily coronavirus update on Wednesday, August 12, it announced it had lowered the figure for “tests made available” by about 10% and discontinued the metric.

An update on the page read: “An adjustment of -1,308,071 has been made to the historic data for the ‘tests made available’ metric. The adjustments have been made as a result of more accurate data collection and reporting processes recently being adopted within pillar 2.”

The Department for Health and Social Care (DHSC) said the changes affected data reported between 14 May and 12 August. It said there had been “a double-counting of test kits that had been dispatched”, “which had not been removed from the lab’s processed data”.

The changes were made after it was discovered fewer in-person pillar 2 tests had been carried out than originally reported, while more tests had been sent to NHS trusts and care homes. The problem was acknowledged by the DHSC on 6 July but the tests were removed from the data on 12 August.

Pillar 2 tests involve all testing done outside hospitals through commercial companies. For example, swab tests carried out at satellite testing centres, such as care homes, and home swab testing kits delivered by post.