It comes after senior Tory MP Bernard Jenkin joined Labour calls for the failing service’s executive chair to be removed from her post following a series of errors and missed testing targets.
Downing Street defended Harding on Monday, however, as the PM’s official spokesperson said: “I think we’ve certainly set out before that the prime minister continues to have full confidence in Dido Harding.
“NHS Test and Trace has built a testing capacity of over 360,000-a-day from a starting point of 2,000-a-day in March – that is a bigger figure per head than in France, Germany, Italy and Spain. 1.1 million have been contacted and told to self-isolate.
“But as you’ve also heard the Prime Minister say, the system does need to improve especially in terms of the turnaround times for tests and we expect that to happen.”
No.10 also said the service was still on target to increase coronavirus testing capacity to 500,000 per day by the end of the month, despite the deadline approaching in only five days.
“The target still stands and I think we have set out that it is our intention to meet that figure by the end of the month,” he added.
“It [the target] is capacity for 500,000 per day.”
Pressed on how the current capacity would increase from 369,000 to 500,000 in such a short amount of time, the spokesperson added: “We have known throughout that the target was to have a capacity of 500,000 by the end of [October].
“We are working to get additional laboratory capacity coming on stream.”
Jenkin had said Harding “should be given a well-earned break”, adding that the PM’s “immediate priority is to fill the vacuum of leadership” at the service.
Writing in the Sunday Telegraph, Jenkin, who chairs the powerful Commons liaison committee, said the failing service needs a shake-up.
He said: “Dido Harding, head of NHS Test and Trace, apparently says that she is struggling with what she inherited when arriving in the role, but during the summer, initial urgency subsided. [...]
“Perhaps some of those exhausted leaders on the government frontline, like Dido Harding, could be given a well-earned break [...]; they could use their hard-won experience to help this group reflect on the lessons learned so far.”
It comes after the service hit another new low on Thursday, reporting its worst ever figures for tracking down close contacts of people with Covid.
Just 59.6% of cases in England were reached and told to self-isolate to stop the spread of the virus.
The government has said 80% of contacts must be reached for the service to be effective, a point underlined by chief scientific officer Patrick Vallance on Friday.
“The challenge for the government is becoming one of public confidence,” Jenkin writes. “Much incredible work is being done, but we are still a long way from the ‘world-beating contact tracing system’ promised in June.
“Announcing fresh targets [now 500,000 tests a day by the end of October] does not instil confidence, because people lack faith that there is a coherent plan.
“Instead, ministers should see this as an opportunity to make changes. This change must be visible and decisive.”
Labour has called for private contractor Serco, which has also been repeatedly criticised, to be removed, and for test and trace work to be handed to local public health teams.
Shadow mental health minister Rosena Allin-Khan also said on Sunday that Harding should go.
“Her position is very difficult. It’s untenable, really,” she told Sky News.