Nadine Dorries has warned the Conservatives could face “complete wipeout” at a general election and urged Liz Truss to stop being a “disrupter”, while a cabinet minister called on warring colleagues to back the prime minister. After a week of bitter feuding overshadowed this week’s Tory party conference, Dorries said Truss should “start engaging with the parliamentary party”. Despite some MPs plotting to oust their leader before Christmas, Dorries said there was “no process for that to happen” and that Graham Brady, the head of the 1922 Committee of backbenchers, should instead go to see her carrying an olive branch. It came as a major push by cabinet ministers to encourage unity was under way. Nadhim Zahawi, the chancellor of the duchy of Lancaster, said the government had 24 months to deliver on the growth plan, and added: “Any dither or delay will end in defeat.” Other pleas for harmony came from Suella Braverman, the home secretary, and Penny Mordaunt, the Commons leader, both of whom were accused of stoking in-fighting during the party conference in Birmingham. As Truss’s approval rating sank to a new low of -47, Zahawi said he did not believe she would be removed and instead MPs would “get behind” her. Increasing Britain’s energy resilience, letting people get a GP appointment in two weeks and bearing down on “bad migration” were cited by Zahawi as subjects that the government would focus on. “What Liz wants to see is not just announcements, but delivery, she wants to see outputs,” Zahawi told Sky News’s Sophy Ridge on Sunday programme. However, Truss’s agenda was called into question by Dorries, who said the prime minister should not chuck the party’s old policies under Boris Johnson and stick to the 2019 manifesto platform. “We can’t throw what they voted for out, because then we’d completely disenfranchise the voting public,” she told BBC One’s Sunday with Laura Kuenssberg show. She added: “The simple principle of our democracy and our unwritten constitution is that if you’re going to have a completely fresh mandate, a completely fresh set of policy ideas and a new prime minister, it would be right to go to the country.” If a general election was held tomorrow, Dorries said the result would “probably mean a complete wipeout for the Conservative party”. But the former culture secretary said Truss “doesn’t need to do that, and I really hope she won’t do that when we’re 30 points behind in the polls”. She said: “I think also No 10 need to take a step back and they need to think also about how they unify the party and the policies and how together we do what is right to move forward.” Despite Truss saying she is willing to be unpopular, Dorries said that “what we don’t need is a disrupter, what we need is a unifier”. She added she was still one of the prime minister’s “biggest supporters” and it was “extremely unlikely” Johnson would attempt a comeback. Meanwhile, Labour warned the UK’s economy was in a perilous situation and blamed Kwasi Kwarteng’s mini-budget for recent turmoil in the markets. Jonathan Ashworth, the shadow work and pensions secretary, told Sky: “It led to gilt yields rising, it led to a run on pension funds and now mortgage costs are soaring so people coming off a mortgage, and this year about 1.8 million of them will be doing that in the next 12 months or so, are facing a mortgage increase of hundreds of pounds every month as a consequence … “We need stability in our economy, instead what we’ve got is a reckless approach, a spike in borrowing costs and now the government, as we understand it, are talking about asking working mums and dads, disabled people, poorer pensioners, to pay the price for that recklessness.”