The current lockdown ends on Wednesday, and Shropshire, Telford & Wrekin will be placed into Tier 2 of the new system. MPs are due to vote on it tomorrow, and many are unhappy with the tighter restrictions.
The Prime Minister has told MPs that the system has a "sunset" expiry date of February 3, but Wrekin MP Mark Pritchard has said he'll only back Mr Johnson if the approach as a whole is reviewed earlier.
He said: "As long as the local infection rate continues to decrease I will be pushing the government hard to get Shropshire and Telford & Wrekin into Tier 1 before Christmas.
"I will only agree to support the government at the vote if the tier system for the country as a whole is reviewed within a shorter period. We cannot continue to have a stop/start approach in tackling this pandemic.
"Jobs need to be saved as well as lives. The balance needs to be got right."
In the letter, the PM also said tiers will be reviewed every two weeks and areas can move down the tiers from December 16, MPs will have another vote on the approach at the end of January and decide whether measures stay in place until the end of March, and the government will publish the circumstances that need to change for an area to move down a tier
Shrewsbury & Atcham MP Daniel Kawczynski described the issue as one of the most polarising in his 15 years representing the area, but is backing the PM.
"The government has taken control of this itself and taken the power away from local authorities because of Andy Burnham (mayor of Greater Manchester) and his pontification over this issue to an extraordinary degree in the national media," he said.
"We cannot run a system like that where local authorities and the government are at loggerheads. That's why the government has had to take control.
"In Shropshire, I'm getting about a 50/50 response. It's a hugely polarising issue.
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"There are those who are appreciative of what is being done and want the government to continue with this cautious approach until Easter, when things are much more likely to start getting back to normal. Then there are others who are furious with the damage it's doing to their businesses.
"I've decided I'm going to support the Prime Minister. The government is spinning a lot of plates in the air at the moment, not least the Brexit negotiations.
"The PM has offered another vote on January 27 and promised a sunset clause which means current rules end on February 3, so the government has compromised too. Let's not blow it now just as the vaccine rescue is coming into view."
Ludlow MP Philip Dunne said he "regrets" that the county is in Tier 2, but believes a cautious approach is correct to help the NHS cope with demand.
"I regret the fact that Shropshire is going to be in Tier 2, but I think the decision to tighten restrictions to prevent the NHS being overwhelmed is the right thing to do," he said.
"It's the same issue as in the first wave, can the health service cope with more pressure from Covid?
"The difference between now and then is we've got the annual winter pressures which impose a greater demand for healthcare. The one bit of good news is that is seems the normal winter flu outbreak is milder.
"Local authorities have been involved. I've been talking to regional health officials in the last week."