Almost a quarter of a million people who came close to someone who tested positive for coronavirus were not contacted by the £12bn test and trace system, according to a new analysis.
Private firms Serco and Sitel failed to get in touch with 245,481 people in England over four months, the figures show.
Boris Johnson's Government has defended the system in the wake of criticism from Labour who claim test and trace is 'on the verge of collapse'. Downing Street says 900,000 people have been told to self-isolate.
The Prime Minister promised the £12bn system would be 'world-beating' when he announced it in May.
Shadow Cabinet Office minister Rachel Reeves said: “We are at a decisive moment in our efforts to tackle coronavirus, and these figures are a new low for a test and trace system on the verge of collapse.
“The Government is wasting hundreds of millions on a system that doesn’t seem to function or even use basic common sense.
“The Prime Minister must act now to reverse this trend. That is why Labour is calling for a short, sharp circuit break to fix testing, protect the NHS and save lives.”
The figures showed that the private firms did reach 372,458 contacts in the period of the data, May 28 to October 7.
“Complex” cases – which include outbreaks linked to hospitals, care homes, prisons or schools – are handled by local health protection teams, which statistics show have far higher rates of success.
A Department of Health and Social Care spokesman said: “We’re continuing to drive forward local contact tracing as part of our commitment to being locally-led, with more than 100 Local Tracing Partnerships now operating, and more to come.”
He added that, when including local teams, 84% of contacts had been traced “where communication details were provided”.
