The National Police Chiefs' Council (NPCC) said that in some forces, functions such as control room operations are being hit by high numbers of absent staff, affecting their ability to respond quickly to calls.

       An NPCC spokesman said: "Nationally, the police officer and staff absence rate is 7.3 per cent. However, in some forces some functions, such as control rooms, are experiencing higher levels of absence.

       "Absence rates in control rooms affect a police force's ability to respond promptly to calls from the public, in particular emergency calls."

       The revelation comes as a leading epidemiologist claimed the NHS Covid-19 app is no longer useful.

       Professor Tim Spector said: "I think employers should tell their staff if they feel unwell, they have cold-like symptoms, then they stay away.

       "But I don't think the app saying that someone might have passed them by in a supermarket is actually that useful anymore in the current state of the pandemic."

       He went on: "I think employers have got to just use common sense."

       Steve Turner, police and crime commissioner for Cleveland, called on the Government to test healthy emergency workers daily so they will not automatically be taken off frontline duties.

       He said: "We suddenly find ourselves cancelling rest days and cancelling leave and bringing officers in from other shifts to cover where we have got the gaps.

       "Our call times will go up, we will miss some calls we would normally pick up."