Liz Truss has always been more popular with Tory party members than with Tory politicians. The moment of greatest peril for her in the Conservative leadership race was when MPs were whittling down the final two candidates.

After being knocked out in the second round, Suella Braverman urged her Brexiteer backers to get behind the Foreign Secretary. Many refused to do so and instead supported Kemi Badenoch, which meant that Truss’s vote count only went up by seven MPs. The momentum could have moved to Badenoch, then behind by just 13. ‘It was the most stressful point of the contest,’ recalls a supporter of the Foreign Secretary.

Eventually Truss made it to the final two and united the right of the party behind her. She now looks on course to enter No. 10 in just under two weeks’ time. A government-in–waiting is being assembled at Chevening, her grace-and-favour home, where aides duck in and out for meetings. Access to the prime minister-to-be is limited as plans are finalised and staffing decisions made.

But to have any hope of making it past the spring, Truss needs to win over sceptical MPs. Of all the problems facing the next prime minister – from economic Armageddon to the NHS – one that should not be under-estimated is managing an unruly parliamentary party in which even now just over a third of MPs back Truss.

Recent events have demonstrated that Tory MPs are a rebellious bunch. Boris Johnson won a very personal mandate and commanded a majority of 80, but was thrown out after less than three years. Many of the 2019 intake care little for parliamentary convention; instead, they prioritise their own brand of politics. Meanwhile, the more senior ranks are filled with former ministers who believe their careers are all but over. Michael Gove has admitted this, and Dominic Raab is likely to be next.

Any new leader would find themselves in a weak position when it comes to controlling these forces. It won’t take long for the new prime minister to discover how small the majority (now 71) really is.

Plenty of MPs believe Rishi Sunak would have the toughest time uniting the party. While it was Sajid Javid’s resignation that started the rebellion, Sunak has absorbed blame for Johnson’s demise. ‘He would face a campaign against him from day one from people who cannot be controlled,’ predicts a government aide. A party strategist says: ‘Who would fare best in a general election and who would best manage the party are two different questions with different answers.’

But life will not be easy for Truss. While she has the highest number of MP backers, at 154, many only declared once it was clear she had a poll lead over 30 points. ‘A lot of people are backing Liz for their careers,’ says one Tory MP. ‘Sadly, I don’t think there are enough great offices of state to go round.’

The more important figure is the number of MPs – 202 – yet to come out in her favour. While Truss wants to strengthen ties between No. 10 and the party, her team accept that some MPs will not be brought back to the fold. Tories in Lib Dem-leaning seats fear that Truss’s election will spell the end of their parliamentary careers. ‘There is a group of about 70 MPs who will never get behind her,’ says an MP with experience of the whips’ office. A government aide adds: ‘It’s not the tax cuts that will lead to rebellion, but other policy issues that MPs think are safe to rebel on.’

While the ‘one nation’ caucus is largely sceptical of a Truss premiership, the hope is that by bringing some members of their wing on board, such as Tom Tugendhat and Robert Buckland, others could be persuaded to support Truss. That said, the bulk of cabinet positions are being reserved for loyal Truss backers. After Sunak suggested in a BBC interview that he would not serve in her cabinet, Truss may not even go through the motions of offering her rival a role.

Those under consideration for the junior ministerial ranks will be more easily forgiven.‘It’s not a crime to back Rishi, but it’s not fine to continually go on the attack,’ says a Truss ally. ‘We want to bring people together,but they are still attacking us.’ Sunak backers who are on the offensive – such as the Treasury select committee chair Mel Stride, who this week urged Truss to ‘come clean’ on her tax cuts – will probably be left on the sidelines. Less proactive Sunak supporters will be offered an olive branch.

While the Sunak camp plans to keep going until the bitter end (‘It’s not over. We will ask the questions that she refuses to answer,’ says a campaign member), once the contest is finished it could be a different story. Those close to Sunak suggest that he is unlikely to cause havoc; it’s not really his style. Instead, he thinks the party needs to come back together after the contest.

Johnson could prove less passive. For now, the outgoing PM and his loyalists are behind Truss – in large part to stop Sunak. ‘It’s clear where his vote lies in the contest,’ says an aide. But if she wins, that could change. ‘Boris on the backbenches is a danger to any successor,’ says a senior MP. ‘He still has support.’ He believes his time was cut unfairly short. When the going gets tough, expect cries to grow louder that Johnson would handle things better.

MPs question how long Johnson will remain in the House of Commons. He could tire of declaring his post-prime-ministerial income and quit, as David Cameron did. Or the privileges committee investigation into whether he misled parliament could result in a by-election that he might lose. But the polls suggest that Tory voters maintain their affection for Johnson, so Truss will be keen not to make an enemy of him. Instead, he could be satisfied with a new passion project. His support for Ukraine – and his near hero-status in Kyiv – means he could be given an international role, such as helping to restructure Ukraine in the aftermath of the invasion.

The prospect of a general election may also help unite the Conservative party, as MPs pull together to try to keep their seats. If that doesn’t do the trick, exhaustion might. ‘The party is tired, MPs are tired. There’s a chance that by the time a new leader is in place there isn’t any fight left,’ says a supporter of Truss. Given that Tory MPs are already complaining that the contest has dragged on far too long, Truss’s best hope for unity may lie in the fact that many of them can’t face another round of Tory bloodletting.