British Prime Minister Boris Johnson has urged his Conservative Party lawmakers to back the Government’s tier-based Covid-19 lockdown in a Parliament vote in a letter stressing that there “a sunset” clause — or expiry date — of February 3 on the latest restrictions.

In an attempt to curb a growing rebellion within his own ranks against the new measures which face a House of Commons vote next Tuesday, Johnson wrote on Saturday evening that the tiers will be reviewed every two weeks, and areas can move down the tiers from mid-December.

“Regulations have a sunset of 3 February. After the fourth fortnightly review (27 January), Parliament will have another vote on the tiered approach, determining whether the measures stay in place until the end of March,” he wrote.

In his attempt to placate angry MPs opposed to further lockdowns, he also committed to publish more data and outline what circumstances need to change for an area to move down a tier, as well analysis of the health, economic and social impacts of the measures taken to suppress coronavirus.

Most of England’s population is set to fall under the two toughest tiers when the second national lockdown ends on December 2. Around 32 million people – covering 57.3 per cent of England and including London – will fall into Tier 2 or high alert level which means the rule of six applies with up to six members of different households allowed to meet outdoors.

Hospitality venues are allowed to open but operate under these strict rules, with dining indoors restricted to single households and support bubbles and alcohol sale permitted only with a substantial meal.

Besides, some 23.3 million people — or 41.5 per cent of the population — are going to be placed in the highest alert level of Tier 3, which prohibits any mixing of households and hospitality venues allowed to open only for takeaways.

Only three regions of the Isle of Wight, Cornwall, and the Isles of Scilly will be under the lightest Tier 1 controls where the rule of six applies overall and most venues are allowed to function near normally.

The further tough measures after four weeks of a stay-at-home lockdown has triggered a backlash among Johnson’s own Tory MPs and the changes could now face a fight in Parliament after the Opposition Labour Party remains undecided and may abstain in the vote on Tuesday.

The Cabinet has been rallying around to try and ensure the latest measures to curb the spread of coronavirus infections clears the Commons hurdle.