Monday brought us the marmalade dropper reshuffle with the return of former prime minister David Cameron.

But when it comes to the fate of Rishi Sunak’s government with voters, Wednesday could well prove a much more consequential moment.

Politics Hub: Braverman launches scathing attack on PM

Because tomorrow the Supreme Court will rule on whether the government’s plan to send asylum seekers to Rwanda is lawful. Mr Sunak hung his premiership on stopping small boats and made deportation to Rwanda the centrepiece of this immigration plan.

And one person who knows the enormity of this moment is former home secretary Suella Braverman, who for the past year has been trying to work out the policy.

Her incendiary post-sacking letter to Mr Sunak this evening was a pre-emptive strike against the prime minister.

For all the astonishing turns of phrase in the letter, the aim of it was simple: What she was trying to do was pin any failure of the Rwandan policy on the PM, accusing him of failing to come up with a Plan B in the event the court rules against them.

Rishi Sunak welcomes ‘strong and united’ cabinet after sacking Suella Braverman – as Cameron joins top team

‘Quick to anger’ Rishi Sunak’s smile ‘not always genuine’, claims Nadine Dorries

From failed Remain campaign to pints with Chinese premier – what does David Cameron’s global track record look like?

Please use Chrome browser for a more accessible video player

“In the event of defeat, there’s no hope of flights this side of an election,” she said. “You have no appetite for doing what is necessary, and therefore no real intention of fulfilling your pledge to the British people.”

So even before the verdict is in the political challenge for the prime minister tonight is even more intense, and while the debate will rage about whether the Rwanda deal can really fix the small boats issues anyway, what has been put into play is the reputation of a prime minister on a flagship policy that he championed.

He needs to show lapsed or wavering 2019 Conservative voters that he is fighting tooth and nail for them on immigration, and the visual of asylum seekers being boarded on to flights and sent out of the country to Kigali is his antidote to the image of those people arriving on the south coast in small boats.

Perhaps pessimistic that the ruling will not go in the government’s favour tomorrow (the verdict is back from the court far sooner than originally suggested), Home Office minister Robert Jenrick took a pre-emptive strike on Tuesday, telling the Daily Telegraph the policy will go ahead “no ifs, not buts”, arguing that the plan to send illegal migrants to Rwanda was at the heart of the government’s promise to “stop the boats in their entirety”.

Sky News Monday to Thursday at 7pm. Watch live on Sky channel 501, Freeview 233, Virgin 602, the Sky News website and app or YouTube.

One Whitehall figure told me that Mr Jenrick, who distanced himself from Suella Braverman on style, was aligned with her on the substance of the Rwanda policy and is prepared – as she was – to do whatever it takes to make Rwanda work.

“If the court goes against the government tomorrow, the question is: what now? How firm is the government willing to be? Will the PM be willing to do whatever it takes? That is the big unknown.”

Read more on this story:
Sunak welcomes ‘united cabinet’ after Braverman sacking
Reshuffle shows PM is done with playing it safe
Leaked WhatsApps reveal fury of Johnson-backing Tory activists

The new Home Secretary James Cleverly has publicly made it clear he doesn’t want to pull out of the European Court of Human Rights (ECHR), in contrast to his predecessor Ms Braverman.

Mr Jenrick is also thought to be supportive of leaving or derogating from the ECHR in order to get flights off the ground. The scheme was put on hold in June last year after the ECHR granted a last minute injunction, blocking the first planned flight.

Click to subscribe to the Sky News Daily wherever you get your podcasts

However, with the ECHR unpinning the Good Friday Agreement and devolution, this is something the prime minister has been perhaps more reluctant to pursue, instead pushing world leaders at a summit with the president of the ECHR earlier this year to win backing for UK attempts to overcome rules that blocked flights.

Government figures argued on Tuesday that if they lose the court judgment on Wednesday, withdrawing from the ECHR at this stage is not on the cards.

But what is on the cards is a re-opening of Tory battle lines. A ruling against the government was always going to open up these divides within the Conservative Party on quitting the ECHR, and Ms Braverman is not just making it clear she wants to lead the charge from the backbenchers but is also accusing the prime minister of letting Conservative voters down.

Already a pivotal moment for him, now the stakes are even higher.

Related posts:

Sturgeon should quit if she broke ministerial code, says Scots Labour leader Questions raised over how new No 10 chief of staff will manage three jobs at once Boris Johnson misses red wall summit for surprise visit to Kyiv Sir Keir Starmer returns questionnaire to police investigating ‘beergate’ episode Rail strikes will ‘punish millions of innocent people’, govt warns Keir Starmer says he ‘hated’ being investigated by police over beergate Braverman avoids press questions after travelling to Manston in military helicopter Memorable political ‘attack ads’ and their impact on elections Liz Truss to urge West to ‘get real’ about China threat in comeback speech Keir Starmer says he has ‘always been confident’ no rules were broken when he hired Sue Gray Boris Johnson hits out at ‘bone-headed’ ULEZ – despite it being his idea Braverman’s inflammatory language will raise temperature in parliament – but plays to Tory gallery