She said: "Despite you having been rejected by a majority of party members during the summer leadership contest and thus having no personal mandate to be Prime Minister, I agreed to support you because of the firm assurances you gave me on key policy priorities."
Braverman claimed the Prime Minister's priorities included reducing illegal migration, delivering on post-Brexit commitments and issuing statutory guidance protecting biological sex in schools
However, the 43-year-old also slammed Sunak ahead of tomorrow's Rwanda ruling and over his response to pro-Palestine protesters.
Critics had blamed Braverman for stoking tensions ahead of last Saturday’s protests which saw thuggery from the far-right and pro-Palestine sides.
Despite putting enormous pressure on the Prime Minister, the ex-Home Secretary stopped short of calling for Sunak to quit as she stressed she will "continue to support the Government in pursuit of policies which align with an authentic conservative agenda".
Sunak's response indicated that the Prime Minister believes in “action not words” and will continue to tackle small boat crossings.
A Downing Street spokeswoman said: “He is proud that this Government has brought forward the toughest legislation to tackle illegal migration this country has seen and has subsequently reduced the number of boat crossings by a third this year.
“And whatever the outcome of the Supreme Court tomorrow, he will continue that work. The Prime Minister thanks the former Home Secretary for her service.”
Braverman's letter comes with Sunak's Tories continuing to flounder in the opinion polls.
Critics had blamed Braverman for stoking tensions ahead of last Saturday’s protests which saw thuggery from the far-right and pro-Palestine sides
Labour consistently register comfortable double-digit leads, with some surveys suggesting Sir Keir Starmer is ahead by around 24 points.
The Conservative Party have also failed in a number of by-election contests, including last month's double-whammy defeats in Tamworth and Mid Bedfordshire.
Braverman was sacked as Home Secretary in Sunak's reshuffle yesterday after writing an incendiary piece accusing the Metropolitan Police of "playing favourites" when it comes to policing protests.
She was previously sacked from Truss' Cabinet after being accused of a security breach.
James Cleverly moved over to the Home Office after serving as Foreign Secretary and former Prime Minister David Cameron was also brought in to succeed the Braintree MP.
Labour consistently register comfortable double-digit leads, with some surveys suggesting Sir Keir Starmer is ahead by around 24 points
Cameron, who described his Cabinet return as "not usual", became the first peer to serve as Foreign Secretary since Lord Carrington.
The last ex-Prime Minister to return to Cabinet after leaving Downing Street was Alec Douglas-Home.
However, the pivot towards the centre appears to have enraged the right-wing of the Tory Party.
"This is exactly what Sunak promised in the past and she’s spot on", a source close to the European Research Group told GB News.
When asked if Braverman's letter showed she was now Sunak's natural successor, the insider added: "I think even Stevie Wonder can see that."
However, a Sunak-supporting MP suggested divisions were emerging between pragmatic Tories and ideological Conservatives.
The MP told GB News: "I think it is typically self-obsessed and tin-eared to the concerns of the vast majority of her colleagues who want an electable Tory Party not an ideological one."
"This is properly woman scorned stuff," a Minister added.
David Cameron was appointed the new Foreign Secretary in a surprising move by Rishi SunakPA
A number of Tory MPs openly criticised the Prime Minster ahead of Braverman's coruscating letter.
Dame Andrea Jenkyns, a loyal Johnson supporter, submitted a letter of no confidence to 1922 Committee chairman Sir Graham Brady yesterday after declaring "enough is enough".
Former Tory leader Sir Iain Duncan Smith admitted he was "sorry" to see Sunak sack Braverman, adding: "She is a highly intelligent lawyer and she understood the real threat we’re faced with in terms of getting these boats stopped."
Penistone & Stocksbridge MP Miriam Cates and Devizes MP Danny Kruger, from the New Conservatives Group, published a damning letter accusing the Prime Minister of "walking away from 2019 voters".
Conservative Democratic Organisation chairman David Campbell-Bannerman also told GB News: "The CDO has been inundated with messages of disgust at the treatment of Suella - that last true Conservative in the Cabinet they say.
"I am afraid that members are leaving in droves and some heading to Reform on seven per cent now."