In the past 48 hours the former chancellor has accused leadership opponent Liz Truss of having policies that would plunge millions into poverty, and refused to rule out voting against her fiscal plans.
If that wasn’t enough, he’s also criticised the Covid lockdown policy he was so frequently sent out to defend, saying empowering Scientific Advisory Group for Emergencies (SAGE) scientists left us “screwed”.
Mr Sunak said he “wasn’t allowed to talk about the trade-off” during the early phases of the pandemic and suggested SAGE edited its minutes to hide dissenting opinions.
These are not comments that will help him win, but instead attacks that will adorn Labour leaflets and rule him out of any consolation role in Cabinet.
It is not so much a change in tact as a full-on U-turn, a doubling down from a candidate who previously said only he could defeat Sir Keir Starmer.
His claims appear to be more about being proved right than winning, laying the groundwork to say “I told you so” at a later date.
Allies of Ms Truss have reacted with fury, accusing him of “thrashing around all over the place like a wounded stoat”.
Another added: “Are you trying to destroy this party? These attacks are framing us as Tory scum. It’s personal and bitter and it needs to stop”.
Such an escalation is to be expected during the closing stages of a race, but with it seemingly already won, some Tories expected more restraint.
Mr Sunak may well be right, but there is no question his actions are not in the interests of the Conservative party.
Ms Truss will not change her plans because of his comments, nor is she less likely to become prime minister.
Saying the right thing now, when it’s too late to change the result, seems desperate and suggests Parliament’s richest MP knows it is over.
It also leaves him potentially untarnished if Ms Truss, as expected, struggles to deal with the cost-of-living crisis and loses the next general election to Sir Keir and Labour.
Mr Sunak may be playing the long game, but it remains to be seen how much of the party will still be around to save.