Self-isolation is still a key part of the fight against coronavirus, a Government minister has said after more than 10,000 critical workers in the food sector were told they would not need to quarantine if “pinged”.

Pressure is mounting on the Government to bring forward the date at which people who are double vaccinated against coronavirus can avoid self-isolation as emergency measures to protect food supplies were launched on Thursday.

The move – along with a limited relaxation of self-isolation rules in other key sectors of the economy and vital public services – will see thousands of workers at up to 500 critical sites avoid the need to self-isolate if identified as a contact of a coronavirus case, and instead take daily Covid tests.

Environment Secretary George Eustice told Sky News on Friday: “All of the people working in those key strategic sites, distribution depots and those manufacturing facilities will be able to use this scheme, and probably well over 10,000 people.”

A small number of named people in other industries such as transport will also be able to be free from self-isolation if they have received both doses of the coronavirus jab.

It comes after it was announced earlier this week that healthcare staff would be exempt from self-isolation.

But Dr Chaand Nagpaul, BMA council chair, said on Friday it is a “desperate and potentially unsafe policy that does not address the root problem”.

He added: “Widening this scheme out to other workplaces for employees in other sectors who should be isolating should only happen in the absolute rarest of cases and with rigorous infection control measures and assurances of safety.”

Mr Eustice defended the scope of the plans and told Sky News: “The reason we’ve made a special exception for food is for very obvious reasons – we need to make sure that we maintain our food supply, we will never take risks with our food supply.

“When it comes to other sectors, yes, of course the fact that they are also carrying high absence levels is causing some stress for them and making it more difficult.

“You also have to bear in mind why we’re doing this and we are trying to still just dampen the pace and the velocity at which this infection is spreading because we have to keep a very close eye on those hospitalisations.”

Former health secretary Jeremy Hunt said the Government risks “losing social consent” for isolation if it does not immediately bring forward the relaxation of quarantine rules for the fully vaccinated, currently planned for August 16.

This was echoed by former business secretary and current chairman of the Commons Science and Technology Committee Greg Clark.

The Tory MP told BBC Radio 4’s World At One: “We know that on August 16 a new system will come in, in which you can take a test if you’re named as a contact and only isolate if you’re positive – I don’t see why we can’t begin that now on July 23 rather than wait.”

But Mr Eustice told Sky the date “at the moment is not coming forward”.

He said: “Things can always change in either direction but the reason we set these days is to give people some kind of indication about what they can expect.”

The need for action was underlined as latest figures showed a record number of people in England and Wales were “pinged” as contacts by the app and told to self-isolate for up to 10 days.

NHS figures show 618,903 alerts were sent to users of the app in the week to July 14, a period before England’s restrictions were lifted and more social contact was allowed.

Industry leaders have warned they will still face staff shortages and lost revenue because of the number of workers having to self-isolate despite the plans.

The Local Government Association said directors of public health were already being overwhelmed with queries from employers who believe their staff should be exempt, and services provided by local authorities such as bin collections, road repairs, and park maintenance could be hit.

Hannah Essex, co-executive director of the British Chambers of Commerce, said: “Pilot schemes for ‘test to release’ options have been running for some time now and we would urge the Government to immediately bring forward the results of those test schemes and set out how this could be used to enable more double-vaccinated people to avoid self-isolation beyond this narrow group of critical workers.”

John Foster, CBI director of policy, added that while the food industry measures should be welcomed, those for other critical workers would become “rapidly become significantly challenged”.

He said: “If the daily contact testing scheme is deemed as a good, safe solution by the Government, the next step must be to scale this up at pace. This scheme illustrates what it is to live with the virus.”