Rishi Sunak’s attendance at the UN Climate Change Conference, COP27, in Cairo last week was his first major appearance on the global stage as UK prime minister. He has sought to portray himself as a reliable, safe pair of hands after the relative chaos overseen by his two predecessors, Boris Johnson and Liz Truss, and his team had hoped that COP27 would be a chance to showcase Britain’s new stability to the world. However, even before he arrived Sunak partly undermined this by wavering over whether or not he would attend at all, confirming that he would only at the last minute. When he arrived in Sharm El-Sheikh, his message of stability was further called into question by events unfolding at home: One of his ministers, a close political ally, was accused of bullying colleagues and forced to resign. The minister in question, Gavin Williamson, had been sacked from previous ministerial positions and accused of bullying before Sunak appointed him. Immediately, the opposition Labour party, and some in Sunak’s own Conservative party, raised questions about the new prime minister’s capabilities as a judge of character. Whatever honeymoon period he might have hoped to enjoy was seemingly over. Far from projecting an image of stability, the new premier appeared to be overseeing yet more uncertainty. This, of course, is unsurprising. There is a new leader at the top but the problems Sunak faces are the same ones that helped topple the previous three Prime Ministers: Truss, Johnson and Theresa May. At their heart lie the deep divisions within the ruling Conservative Party. These fractures are complex and fluid. In the past they were ideological; for example, the pro- and anti-Brexit camps that hobbled May’s government. Yet even when Johnson solved this problem by expelling some MPs and orientating the party more firmly into a pro-Brexit camp, new fissures still emerged. Those splits were over Johnson himself — including his repeated mistakes in office and his creative relationship with the truth, particularly over whether he broke his own lockdown rules during the COVID-19 pandemic. Eventually the anti-Johnson group won out and dispatched their leader, much to the outrage of his supporters. The contest to succeed him prompted yet more splits within the party, with MPs coalescing around several candidates in what became a bitter leadership battle.Though Liz Truss emerged victorious in the vote by party members, she faced resentment from many MPs, a plurality of whom had supported her main rival, Sunak. When her initial economic policies proved disastrous, those same anti-Truss MPs acted with brutal speed, toppling her within weeks. Her reign as premier was the shortest in UK history. Though Sunak has tried to present a display of unity by appointing to his government members who previously served in the cabinets of Johnson and Truss, alongside his own allies, divisions remain. It is no coincidence that the MP who first accused Williamson of bullying was a Truss appointee, although a civil servant subsequently weighed in to say he had been treated in a similar way. One of the challenges facing Sunak is to try to hold his fractured party together without it undermining his ability to govern. Another example of this dilemma could be observed during his first week in office and concerned Home Secretary Suella Braverman. She had resigned from Truss’ government for breaching security protocols but days later, after Truss had gone, Sunak reappointed her. Insiders suggested Sunak brought her back because she is a powerful figure with her own following in the Conservative Party, who could prove troublesome outside of government. But as with the Williamson situation, the decision to appoint someone with a questionable record undermined Sunak’s claims of being a leader of integrity and stability. As the Labour leadership was quick to point out, it seemed like he was putting the needs of his party ahead of the country. So, what does all of this mean for Britain’s place in the world? Whatever his hopes for an international reset, if he cannot keep his party in line it will prove difficult for Sunak to make much progress. Arguably the most contentious issue will be Britain’s relations with the EU. Johnson took a highly confrontational approach, especially over the Brexit-related issue of the Northern Ireland protocol governing the border with Ireland, and Liz Truss had promised to replicate this in her leadership campaign. EU leaders were initially hopeful that the aura of reliability and sensibleness projected by Sunak might mean there would be a more conciliatory tone from London, especially now that the UK’s economic troubles mean it cannot afford a trade war with Brussels. However, with hard-line Brexiteers still prominent within the Conservative party, many of whom backed first Johnson and then Truss, they will make it difficult for Sunak to pursue any detente with the EU if his position looks weak. More generally, if Sunak’s administration is riven by the kind of splits, backstabbing and frequent ministerial changes that have characterized the party for the past six years, it will be hard for him to convince international partners that things have changed under his leadership. Indeed, Brexit and its fallout, of which Conservative party infighting is but one effect, has seriously undermined Britain’s global reputation. A change of leader at the top of the Conservative government, however well-intentioned, will not suddenly fix this. This does not mean the UK will be inert internationally under Sunak. Internal rifts will not prevent it from playing a prominent role in supporting Ukraine, or other policies Conservatives are largely united on. But areas of contention, such as relations with the EU or the green policies being discussed at COP27, will be harder for Sunak to push through. Until he is able to unite his party behind him, perhaps by winning a general election, against the odds, or until the fractious Conservatives are voted out of office, Britain is likely to remain divided at home and weak abroad. Even then, such has been the damage caused over the past few years, it will prove to be an uphill task for any new government to reverse course and repair Britain’s reputation as a global player. • Christopher Phillips is professor of international relations at Queen Mary University of London, author of ‘The Battle for Syria’ and co-editor of ‘What Next for Britain in the Middle East?’ Twitter: @cjophillips