Boris Johnson won the battle to contain anger from his MPs and cabinet over the manifesto-breaking tax increase on Tuesday – but restive Tories warned he has not yet won the war. After an explosive few days of briefings from furious but mainly anonymous cabinet ministers and backbenchers, the tactic of keeping them in the dark on the details until the final moment appeared to pay off for the prime minister, with a snap vote called for Wednesday expected to be won comfortably by the government. But the longer-term political problems Johnson is facing show no sign of relenting, with frustration at a chaotic run-up to the announcement. Two likened the current Downing Street operation to the turmoil of Theresa May’s tenure. “He’s got away with it,” a prospective rebel – who ended up speaking in support of Johnson in the Commons – sighed afterwards. Another said the handling of the announcement was a “clusterfuck” but kept their head below the parapet, conceding there were not enough critics to warrant going public. They and others who chose not to openly condemn Johnson for reneging on one of his six election “guarantees” put it down to a several factors: the detail not being as bad as feared from initial reports (in the end, Johnson ensured dividends and working pensioners will not be spared the tax rise); the lack of an alternative plan from the Labour leader, Keir Starmer; and negligible public outcry. Several also praised as “grown up” the prime minister openly admitting on the floor of the Commons that increasing national insurance contributions (NICs) flew in the face of a manifesto commitment not to raise taxpayer contributions. Will Tanner, a former deputy head of the No 10 policy unit under May who is now director of the Onward thinktank, said Johnson “grasped the nettle”. He said: “It would have been far worse if he tried to suggest he somehow wasn’t breaking a manifesto commitment. Because this is a new levy, it would have been possible, but that would have come across as sneaky and duplicitous. The fact he owned it … is something that will be welcomed by voters.” More Tory MPs said they felt uncomfortable with the NICs rise. But they called it “the lesser of many evils” or a “blunt instrument that may need tweaking later”. Another backbencher, Dr Dan Poulter, said he instead favoured a levy on estates after death to raise the cash for social care reform, though he could “understand why the government would prefer to raise national insurance, which is in line with the original proposals” set out by the 2011 Dilnot report into reforming social care. The biggest policy shift since the weekend that appeared to keep critics muted was extending the tax rise to cover working pensioners, who are exempt from NICs. “That really saved them,” a would-be Tory rebel said. But another urged caution, saying George Osborne’s experience as chancellor had proven that “if you wait 48 hours, it can all unravel in the detail”. Some Tories were wary of whispers of a cabinet reshuffle on Thursday – fuelled by a glaring hole in the government’s business that day, a lack of denials by No 10 and two outstanding bits of tinkering: a vacant junior ministerial role in the Foreign Office, and the return to work of Suella Braverman, who had been covered as attorney general during her maternity leave by Michael Ellis. Sonia Khan, a former special adviser to chancellors Philip Hammond and Sajid Javid, said the government was unlikely to “lean away from those rumours because they help you” and could serve to “whip people up into a frenzy”. Khan also suggested some Tories could be suffering from “fatigue” with successive governments’ reluctance to reform social care, and that in the same way some backed Johnson to deliver Brexit, they now thought it would be better for him to just “get social care done”. A former Conservative campaign headquarters insider concluded that No 10 was viewed as “pretty vindictive” by Tory MPs wary of scuppering their chances of promotion, adding: “Once you’re in the cold you’re rarely going to come back in.” Another Tory aide said it was simple game theory. “Yes the odds of a reshuffle are slim, but are you really going to blow up your chances if you might then spend the next two, three years kicking yourself?” Foreshadowing a tricky autumn for Johnson, a minister acknowledged anger at the prime minister from his own MPs could be at its highest level yet. “Nobody knows what the PM stands for other than winning elections, so their loyalty is only to his success,” they said. Another frontbencher said: “He’s developing very early what Margaret Thatcher did quite late on in her premiership – an inability to distinguish what is popular. He’s not as loved as he thinks he is.”