More than half a million people were told to self-isolate by the NHS Test and Trace app last week. A total of 520,194 alerts were sent in the week to 7 July, the highest since the phone app’s launch.

The surge in alerts comes ahead of the 19 July reopening in England, a decision that has prompted anxiety among voters. The initial roadmap, published in Feburary, was perceived by the public as cautious, but a dramatic recent increase in cases and self-isolation requests has been matched by a rise in concern.

Businesses have reported unease over the increasing number of workers who have been told to self-isolate by the app, with the manufacturing trade union Unite warning the system was causing “havoc” on production lines and that factories were on the verge of shutting. 

The requirement to self-isolate if alerted will end on 16 August for people who have received two vaccine doses.