If it is a political truism that a cabinet is all smiles when the ruling party is well ahead in the polls, it is equally the case that nothing highlights ministerial ambitions more than a vulnerable PM. With Boris Johnson on the ropes over lockdown party allegations, all eyes are now on his cabinet colleagues and other senior Tories. Most have offered him support – so far. But will any break cover over the weekend, particularly if there are any new revelations? The Guardian looks at the ones to watch. Rishi Sunak The chancellor’s endorsement of Johnson was one of the latest, and perhaps the most equivocal. Having spent Wednesday 200 miles from the Commons on a visit to Devon, Sunak waited until eight hours after Johnson’s apology to tweet that this had been the correct thing to do and “I support his request for patience while Sue Gray carries out her inquiry.” Since then there has been silence, met by irritation among some fellow Tory MPs about the lukewarm extent of Sunak’s public support for his boss, and how it hints at his apparent eagerness to take over. Liz Truss As another perceived frontrunner to replace Johnson, the foreign secretary’s long delay in tweeting support for the PM – it took until 9.15pm on Wednesday, an hour after even Sunak – was viewed as significant. Unlike the chancellor, Truss has been spotted since, defending Johnson in a BBC interview. Even here, however, the message was not entirely straightforward. While talking up the PM’s wider record, arguing “I think we now need to move on”, a grave-faced Truss said of the lockdown parties: “We are very clear that there were real mistakes made.” Michael Gove The levelling up secretary was given the unenviable task of defending Johnson publicly at the 1922 meeting of Tory backbenchers on Wednesday. He did so robustly, saying Johnson had made the right calls on Covid and laying into Scottish Conservative leader Douglas Ross, who has called for the prime minister to resign. But Gove is likely to have been frustrated that a crucial announcement on dangerous cladding remediation was overshadowed by the continuing rows over parties. And Gove has form for changing his mind. Johnson allies have never quite trusted him since he scuppered the prime minister’s first leadership bid in 2016. Jeremy Hunt The former foreign secretary has been rebuilding his reputation from the backbenches as chair of the health and social care select committee. He has tried and failed in a pitch for the leadership once before, and would be a rank outsider this time too. But some commentators have suggested he might still have a chance – and his quiet manner would certainly be an antidote to the mayhem of Johnson’s chaotic time in Downing Street. Hunt has admitted his ambitions have “waned a bit”, but that might not stop him from sticking the boot in to the man who beat him in 2019. Theresa May Few critics of Johnson have been as forensic as the former prime minister, who was tortured during her own time in No 10 by Johnson. She has described him as “ill-judged and wrong” over his handling of the Owen Paterson sleaze allegations and decried him for threatening to break international law during Brexit trade negotiations. Johnson, she said, had abandoned “global moral leadership.” Is this the moment to exact a final revenge?