A large number of Conservative MPs could still vote against a tiered system of coronavirus restrictions for England next week, a leading backbencher has warned, as Boris Johnson prepared to unveil the new post-lockdown regime for the country. Steve Baker, the deputy chair of the Covid Recovery Group, which sent a letter on behalf of 70 Tory MPs warning the prime minister that any new measures must be justified, said he was “reassured” at news that shops, gyms and places of worship would remain open in all the new three tiers. But as Matt Hancock, the health secretary, said the system, which will come into force from 2 December, will have to be more robust than the tiers in place before the lockdown, Baker said his group remained concerned. “We’ll have to hear what the prime minister says before we decide how we’re voting,” he told BBC Radio 4’s Today programme. Baker reiterated his group’s demand that the government produce a full cost-benefit analysis of the new tiers. He said: “Yes, and I think it’s a very modest and reasonable thing to ask for.” On Sunday, the chancellor, Rishi Sunak, said such an analysis was unlikely. Baker said: “We do need to stand up for people, because we know that livelihoods matter, we know that there’s nothing quite like poverty for shortening your life and diminishing your life chances. So all of these things continue to matter.” Johnson is due to outline plans for the new regional tiers to parliament on Monday afternoon, although details of which areas will go into which tiers will not be decided until Thursday. He is also expected to unveil outline proposals for a temporary UK-wide relaxation to allow mixing between households over Christmas. Baker said he welcomed the Christmas plan, while saying any restrictions over the festive period were “a major infringement on the right to a family life”. It is understood that all of the new tiers will allow non-essential shops, gyms and places of worship to remain open. Rules for pubs and restaurants will vary between tiers, but will be tougher overall than under the previous system, addressing a well-identified source of infection but dismaying the hospitality industry. Hancock told BBC1’s Breakfast programme that the new regime would be tougher overall than the old tiers. He said: “The tiered system, while lighter than lockdown, will have to be stronger than the previous tiers that were in place.” In particular, he said, the new top tier would be more robust. He said: “We saw that the previous tier 3 could essentially get the cases flat, but not bring them down, and we do need to bring them down.” As part of the new system, the government has said it will expand a system of mass, instant coronavirus testing being trialled in Liverpool. Among the plans is a scheme to stop people who have come into close contact with someone who has coronavirus from having to isolate for 14 days, if tests show they have not contracted it. Contacts will have the chance to be tested every day for a week, and will not need to isolate during that period if the tests remain negative. This would be trialled in Liverpool, and potentially rolled out nationally from January. Hancock said using mass testing to track down asymptomatic carriers of the virus could be hugely effective. He said: “The combination of the mass testing and the measures, in Liverpool, have brought the cases down really quite remarkably, much faster than I would have thought was possible.” A study led by academics from the University of East Anglia has concluded that the previous tier 1 had “little impact” on the transmission of coronavirus locally. The study, which has not yet undergone peer review, examined infection rates over 14 days in regions placed into the three tiers. It found that the top tier, which barred all household mixing, had the most impact, while the impact in tier 2 was mixed. Prof Paul Hunter, who led the study, said: “Our conclusion is that the problem with the tier system was not actually the tiers, but the inability of the government in England to allocate local authorities to their most appropriate tier quickly enough.” On Sunday, a further 398 people died of coronavirus in the UK, according to the government’s daily figures, up from 168 the same day the previous week. A total of 18,662 people tested positive for the virus, down from 24,962.