UNIONS warned today that the compulsory wearing of face masks against the Omicron strain of the coronavirus would be “useless” unless the government enforces it.

The renewed measures include compulsory wearing of face masks on public transport and in retail outlets from Tuesday — but with no government method of enforcing the regulation.

But unions said front-line workers should not be responsible for enforcing the regulations, leaving them open to abuse and even violence.

The government has reintroduced restrictions after the mutant Omicron strain emerged in South Africa.

Flights to Britain from South Africa and several other African countries have been banned.

However the mutant strain has already reached Britain, with three detected in the country as the Star went to print today.

Transport union RMT said its front-line members have faced “public anger” when dealing with passengers who refuse to comply.

RMT general secretary Mick Lynch said: “We support the wearing of masks but there are major issues about enforcement and it’s our members left in the front line with angry passengers who refuse to comply.

“The government must make the resources available to properly police this reintroduction of compulsory face coverings on our transport services.”

Retail workers’ union Usdaw said the measure should be a “legal requirement,” and that it should not have been dumped when the government eased restrictions in England in July.

Unite national officer for passenger transport Bobby Morton said: “It is not sufficient to announce that face masks will once again become compulsory — this policy has got to be fully enforced in order to protect public health.

“The government’s previous inconsistent messaging on face mask wearing is almost certainly going to result in a high degree of non-compliance.

“Unite’s advice to bus drivers is clear: it is not their role to enforce mask wearing, their responsibility is to safely drive and operate the bus. The job of enforcing mask wearing is that of the bus operator and the police.”

He also condemned the lifting of the measure by the government in July.

Mr Morton said: “Unite has consistently warned that the requirement to wear face masks should never have been removed while rates of Covid-19 remained high. 

“It is only the arrival of the new variant which has forced the government to act.”

Retail union Usdaw said the government should be “absolutely clear that it is a legal requirement in England for shoppers to wear face coverings again.”

Usdaw general secretary Paddy Lillis said: “Retail staff working with the public every day are deeply worried about catching Covid-19 and the arrival of the Omicron variant is a further concern.

“Wearing a face covering … should not be a personal preference, but a personal responsibilty.”

He said shopworkers have faced abuse when telling customers to wear face masks — and that they should not have to be responsible for “enforcing the law.”

“We ask the public to follow the rules and respect shopworkers, abuse is not a part of their job,” Mr Lillis said.

“Many shopworkers are at a greater risk of catching the virus and taking it home to their families. 

“Yet they have worked throughout the pandemic to keep the country supplied with essentials. These key workers must be valued, respected and protected.”

Shadow foreign secretary Lisa Nandy said Labour supported measures on wearing masks, but “desperately” wanted to see the government tighten up travel restrictions.