Boris Johnson has defended the new tier system saying it brings simplicity and clarity to the public. It comes as the Prime Minister faces a backlash from Conservative MP’s over the system that will see over 55 million people in tiers 2 or 3.

A group of Tory MPs is threatening to rebel in a Commons vote on Tuesday.

If Labour backs them, this could threaten the government’s majority.

They claim the government is adopting a one-size-fits-all approach, which does not reflect local levels of infection.

Speaking on a visit to Public Health England laboratories, at Porton Down, Mr Johnson said he understood the frustration of those in higher-tier areas.

Boris Johnson at Public Health England labs in Porton Down

He said tough tiering was still more relaxed by a long way than the current lockdown measures and it would “drive the disease down… until a vaccine comes on stream, which we hope will be over the next weeks and months”.

The Covid Recovery Group of Conservative MPs, set up to scrutinise the government’s response to the pandemic, is threatening a revolt in next Tuesday’s vote.

The group claims to have 70 members, but it is not clear how many of them would rebel against the government.

Forty-three Conservatives would have to defy the prime minister to defeat the plan, if all opposition MPs also voted against

Shadow health secretary Jonathan Ashworth said Labour was not against tougher restrictions or tiers, but would seek reassurances on support for the poor and vulnerable.

The frustrations by Mr Johnson comes as the governmenty scientific advisors say theĀ  R number for coronavirus has fallen to between 0.9 and 1 for the first time since August

The aim is to keep R below 1 until a vaccine is rolled out.

During the first peak in the spring, R was thought to be above 3.

However, cases in some regions of England are still high, particularly the North West, the North East, and Yorkshire.

An R rate of 0.9 and 1.0 means that on average every 10 people infected will infect between 9 others

The UK government has said in the past that the R number was one of the most important factors in making policy decisions.