MPs could signal growing discontent with the government’s coronavirus restrictions at key votes on the regulations this week, amid growing calls for the government to publish the scientific advice behind the 10pm curfew on pubs and restaurants in the UK. Conservative and Labour MPs have signalled they could withdraw backing for implementing the rule of six regulation and the curfew at votes expected this week. One senior Conservative MP said a small rebellion was expected on Tuesday on the rule of six statutory instrument – a retrospective vote on the implementation of the new measure under existing legislation. Another vote is expected by MPs to take place on Wednesday on the 10pm curfew – which could attract a more significant rebellion given the measure has also been criticised by the Labour frontbench. One source said it was likely to be “a major problem on the government side”. The government has not yet confirmed that vote will go ahead. The government would not be expected to lose the vote – but should it do so the legislation ordering pubs and restaurants to close at 10pm would expire. MPs are also likely to use the vote as a platform to demand more scientific evidence to support the measure. “There is no basis for it, it is crippling the hospitality sector for no good reason and it chucks everyone out on the street at the same time,” one MP said. “Things could get interesting if the Labour frontbench decide not to support it.” A Labour source said no decision had been made. Johnson’s spokesman urged MPs to approve the measures. “The PM understands the frustrations that people have. But, as prime minister, he has to take a course of action that prevents the spread of the virus and therefore protects the NHS and saves lives,” the spokesman said. “What we are seeking to do is to get the right balance between protecting lives and livelihoods: which is why we’re trying to keep as much of the economy moving as we can. In terms of the rule of six, we think it gives clarity to the public, and is a sensible and helpful step in helping us to control the spread of the virus. He would urge all MPs to vote for it.” Last week, the government agreed a compromise deal with Tory MPs, up to 100 of whom had threatened rebellion on renewal of the Coronavirus Act, promising any new England or UK-wide restrictions would be put to a vote in advance. Downing Street said there was “regular engagement” with MPs on the issue, as well as with the chief whip. A legal challenge has also been launched against the 10pm curfew, which demands to see the scientific advice behind the restriction. The owner of London nightclub G-A-Y, Jeremy Joseph, has said he is seeking a judicial review to overturn the curfew, writing to health secretary Matt Hancock with a formal challenge to obtain the scientific justifications for the policy. “This government has failed to show why the 10pm curfew was put in place and has published no scientific evidence to substantiate its implementation,” Joseph said. The legal team has asked the government to highlight scientific evidence provided by Sage (the Scientific Advisory Group for Emergencies) or other bodies and any impact assessment relating to the curfew by Tuesday. The Guardian revealed on Monday that the government is considering a draft proposal for a three-tier lockdown system, where the most strict measures would include closures of restaurants and pubs, as well as sports clubs. Should those measures be proposed they are also likely to prompt significant disquiet among Conservative MPs. In an interview on Monday, Johnson said it would become clearer over the coming days if the new measures like the curfew and the rule of six were having an effect on the case numbers. “The crucial thing is that in the next few days, week, we’ll see more clearly whether some of the restrictions that we put in – the extra enforcement of the rule of six, the extra enforcement of self-isolation, the rules on masks and so on – all the stuff that has come in, we’ll see whether that starts to work in driving down the virus,” he said.