A technical failure in England’s COVID-19 testing data system has now been fixed and should not be repeated, Work and Pensions Secretary Thérèse Coffey said on Monday.

Britain reported a jump in daily COVID-19 cases to a record 22,961 on Sunday, after authorities said a technical issue had meant that over 15,000 test results had not been transferred into computer systems on time, including for contact tracers.

“The glitch has been found and fixed and I’m sure that the changes are brought in straight away to make sure this sort of problem doesn’t happen again,” Coffey told Sky News.

“I’m sure that PHE (Public Health England) will not be allowing that issue to happen again,” she said.

News of the glitch was likely to cast further doubt over Prime Minister Boris Johnson’s handling of the COVID-19 outbreak: his government’s response has been cast by political opponents as slow, poorly organised and confusing.

Johnson, who promised a “world-beating” test-and-trace system, says there have been missteps but that the government has faced the biggest health crisis since the 1918 influenza outbreak.

The technical problem, which was identified on Friday and has now been resolved, led to 15,841 cases not being uploaded into reporting dashboards used by the National Health Service (NHS) contact-tracing system.

“We fully understand the concern this may cause and further robust measures have been put in place as a result,” said PHE’s interim chief executive, Michael Brodie.

The authority said that all the people concerned had been given their results in a timely fashion, and that those with positive results had been told to self-isolate.