The United Kingdom was the first country to limit international travel over the Omicron variant, raising alarm bells about its mutations, and in December introduced work-at-home advice, more mask-wearing and vaccine passes to slow its spread.

But while cases soared to record highs, hospitalisations and deaths have not risen by the same extent, in part due to the UK's booster rollout and the variant's lesser severity.

Johnson's approach to avoid lockdowns and live with the virus contrasts with a zero tolerance approach to COVID-19 in China and Hong Kong and tougher restrictions in many other European countries.

"Many nations across Europe have endured further winter lockdowns... but this government took a different path," Johnson told MPs, saying the government had got the toughest decisions right and that numbers going into intensive care were falling.

"Our scientists believe it is likely that the Omicron wave has now peaked nationally... because of the extraordinary booster campaign, together with the way the public have responded to the Plan B measures, we can return to Plan A."

Johnson said that none of the so-called Plan B measures would remain as face masks would not be legally enforced anywhere, COVID-19 passes would not be mandatory and advice to work from home would end.

Johnson has faced criticism for his handling of the pandemic overall and the UK has reported 152,513 deaths, the seventh highest total globally.

Scotland, Wales and Northern Ireland have followed their own anti-coronavirus measures, generally with tougher restrictions, but have also begun to ease them.

Johnson hopes to reset his agenda following furore over the lockdown gatherings at his office, which has some in his party plotting to remove him.

Johnson admitted he attended a party in the garden of his Downing Street office and residence in May 2020 while social mixing was banned.

The lifting of Plan B measures, along with Johnson's navigation of Omicron without resorting to a stringent lockdown, could help him appease vocal opponents of restrictions in his own caucus amid the party unrest.

He said that if data supported it, he may end the legal requirement for people to self-isolate if they test positive before the regulation lapses in March.

"But to make that possible, we must all remain cautious during these last weeks of winter," he said, warning of continued pressure on hospitals.

"The pandemic is not over."

A third of the UK's 15 million cases have been reported since the onset of Omicron.

By contrast, the UK has reported 5 per cent of its COVID-19 deaths since the variant was identified in late November.

"The idea was by really trying to put a lot of impetus on the booster program, it would be possible ride it out without the most coercive methods," Professor Francois Balloux of University College London's Genetics Institute, told Reuters.

"In terms of morbidity and mortality, I think it could be seen as probably the right decision."

Australian Associated Press