More than 100,000 people in South London have been told to self-isolate in the past two months.
The latest government data shows that a huge number of people in Croydon, Sutton and Merton have been contacted by the NHS track and trace service between May 28 and July 14.
In Croydon 34,828 were identified by the service but just 28352, or 81 per cent of people were reached.
While in Merton 18,463 people were transferred to the service with 88 per cent, or 16,248 reached.
Over the border in Sutton a total of 17,883 were identified, 90 per cent of whom 16,008 or 90 per cent reached.
The increase in people being told to self-isolate has been branded the ‘pingdemic’ and has led to the government saying ‘critical workers’ including those in food production and transport will be exempt from isolating.
But the chairman of the Local Government Association has called for more clarity on which staff will be exempt.
James Jamieson said: “Directors of public health, working in councils, are already under huge pressure as a result of the need to sign off on self-isolation exemptions for social care staff as well as many daily enquiries from other employers in their local area who believe their staff should be exempt.”