Sadiq Khan has urged Boris Johnson to quickly change the rules so fully vaccinated people do not have to self-isolate if they come into contact with a Covid case.
The push, which is also backed by business leaders, comes amid shortages of staff in sectors such as hospitality, transport, and the food supply chain.
Rail services have been cut back and some pubs and restaurants closed as vast numbers of people are ‘pinged’ be the NHS contact tracing and and told to self-isolate.
Bin collections, the police, and the food supply chain are also among other sectors said to have been affected by absences.
In the capital, some lines of the London Underground have faced problems because of the so-called “pingdemic”.
The government has said workers in some sectors like food supply and power networks will soon be exempt from the requirement if they are double-jabbed – following a similar move for health and social care workers.
And a more general relaxation of the requirement is due to come in from 16 August.
But in a joint letter to the prime minister, Mr Khan joined UK Hospitality, the London Chamber of Commerce and Industry and London’s Federation of Small Businesses said the date should be brought forwards.
“The summer months are crucial for many businesses’ recovery and their ability to recover must not be put in jeopardy,” the letter says.
“We are therefore calling on you to ensure that the necessary testing is in place to enable people who have been double vaccinated for longer than two weeks and pinged by the NHS Covid app, to immediately return to work, following a negative PCR test, rather than having to self-isolate.”
The signatories say this approach would help keep faith in the NHS Covid-19 app. Polling suggests large numbers of people are deleting the app or turning off contact tracing amid a surge in pings.
As many as 608,000 contact tracing alerts were sent in England in the week between 8 and 15 July, according to the most recent available figures – a record high number.
Defenders of the app say it is merely contact tracing a lot of people because a lot of people have Covid and are mixing in public.
But critics say it is imprecise and does not take into account many risk factors like whether a person is outside or in a well-ventilated area.
Friday’s figures showed 36,389 new Covid infections, a lower increase than in previous days.
