Fresh concerns have been raised over police being forced into isolation over Covid-19 contacts after it was said the number of absent Metropolitan Police officers reached nearly one in five.

Policing minister Kit Malthouse conceded on Sunday there has been a “challenge” but insisted changes to isolation rules for critical workers will help ease the so-called “pingdemic”.

He suggested calls from businesses and MPs for the wider exemption for fully vaccinated individuals to be brought forward from August 16 would be rejected.

Ken Marsh, the chairman of the Metropolitan Police Federation representing rank-and-file officers in the capital, said there is confusion over the exemptions for critical workers.

It (fall in absences) has no bearing whatsoever on this new Government nonsense around exemptions - we’re not even sure we’re on the list

He said “a huge strain” was being heaped on officers on the frontline, with 15% in the capital being off on Saturday, down from a high of 17% last week.

But Mr Marsh said the critical workers exemption introduced amid widespread criticism is not responsible for the slight reduction in absence rates.

He told the PA news agency: “It has no bearing whatsoever on this new Government nonsense around exemptions – we’re not even sure we’re on the list.

“We’re being told that officers have to apply for it if they’re specialist drivers and all sorts, it’s not just a carte blanche all police.”

Mr Malthouse said that the 200 new daily testing sites being introduced from Monday in order to facilitate isolation exemptions would help, particularly for critical roles.

“We have had a challenge across the whole of policing on what’s been called the pingdemic,” he told Times Radio.

“Not least because there are particular functions of course where police officers do gather together in close groups, often inside.

“So as you might have seen there has been an announcement where there will be more availability of this daily testing for those who have been double-vaccinated so they can go about their business, particularly in critical roles where we need to maintain capacity like control rooms, like armed response.”

But he suggested the wider relaxation of isolation rules for all fully vaccinated people would not be brought forward from August 16.

“No, I don’t think so, no,” he told Times Radio.

“First of all we want to make sure as many people as possible actually get jabbed.

“Also we need to have the kind of natural firebreak, if you like, of the start of the school holidays where people separate a little bit more, there’s a bit more atomisation, before we get to August 16.”

Scotland Yard declined to comment on the number of officers who are absent due to Covid-19.

“Despite the challenges of Covid-19, the Met is continuing to provide a resilient and strong policing service to London. We are not providing details on sickness or isolation,” a spokesman said.