The outsourced test and trace system has failed to reach nearly a quarter of a million close contacts of people who have tested positive for coronavirus, according to a new analysis.
Private firms Serco and Sitel failed to contact 245,481 contacts in England either online or from call centres over four months - missing nearly 40% of contacts, the figures show.
Labour said the figures show test and trace is "on the verge of collapse" and highlight the need for a short national lockdown to allow the Government to fix the system.
The Government defended the system, saying test and trace is "breaking chains of transmission" and had told 900,000 people to isolate.