All travellers returning to the UK must take a PCR test and self-isolate until they receive a negative result as part of new measures introduced to combat the new omicron variant of coronavirus. And effective Tuesday, face coverings are again compulsory in shops and on public transportation in England.

The reintroduction of mandatory face masks brings England closer in line with the rest of the UK – Scotland, Wales, and Northern Ireland – which had kept some restrictions in place after England lifted all mandatory measures in the summer.

Travellers also face greater scrutiny. Previously they had been able to take a lateral flow test and there was no quarantine requirement.

The government also said it would offer all adults a booster dose of vaccine within two months to bolster the nation’s immunity.

Prime Minister Boris Johnson said the new measures will “buy us time in the face (of the new variant)”. He said that while many people felt an understandable “sense of exhaustion” at the prospect of renewed restrictions, the UK’s position is “immeasurably better than it was a year ago.”

The government said Tuesday that 22 cases of the omicron variant had been identified across the UK, a number that is expected to rise.