Mr Sunak - the first ever Asian to hold the highest office in United Kingdom politics - replaced the deposed Liz Truss yesterday after she lasted only 50 days in the role, a record shortest tenure for a PM.
The markets appear to consider Mr Sunak, who previously worked in finance and was Chancellor of the Exchequer under Boris Johnson, to be a safer and more cautious pair of hands than his predecessor Ms Truss.
For, when it became clear on Monday that Mr Sunak was likely to be unopposed, trading in government bonds quickly rallied with the implied interest rate on these bonds dropping sharply.
That is a far cry from the reaction by the markets to plans laid out by Ms Truss and then-Chancellor Kwasi Kwarteng in their mini-budget on 23 September.
At first, Ms Truss tried to ride out the storm by defending her strategy - and, when that failed, by sacking Mr Kwarteng on 14 October.
That same day, Ms Truss subsequently gave an extremely unconvincing appearance at a press conference - and she was reportedly little better at presenting her vision in a meeting with her backbench MPs, known as the 1922 Committee.
Jeremy Hunt came in as replacement Chancellor and promptly pulled apart the economic plans launched by Ms Truss and Mr Kwarteng.
Meanwhile, Ms Truss - under severe pressure from all sides of the House of Commons at Prime Minister's Questions - declared herself to be "a fighter not a quitter" and committed her government to protecting the Triple Lock on pensions.
The problem with this was that, only a few days earlier, Mr Hunt had not ruled out a review of the Triple Lock policy - and it became evident that Ms Truss was not going to be able to extricate herself fully from her economic ideas.
Just after 1.30pm at 20 October, the 56th Prime Minister bowed to the inevitable.
Humiliatingly, the end of Ms Truss's tenure will be remember for her failure to outlast an iceberg lettuce which had been placed by the Daily Star on a bench alongside a photograph of her.
The newspaper responded to the resignation with the headline, "Lettuce rejoice", and bookmakers offered odds of 500/1 that the lettuce would become the next PM.
Instead, it was Mr Sunak, and he now appears to have calmed the storm in the financial sector.
At the same time, though, the Richmond (Yorks) MP has caused an immediate stir in Westminster by conducting a major reshuffle to remove many of the figures involved in the brief Truss administration.
Mr Hunt remains as the current Chancellor, while James Cleverly - a single person argument against nominative determinism - has retained his position as Foreign Secretary.
However, Steve Barclay, a non-entity of a former Brexit Secretary, becomes the fourth Health Secretary since July - and Gillian Keegan has been named as the fifth Education Secretary of 2022.
Most extraordinarily, though, the reshuffle produced the return of Suella Braverman as Home Secretary who replaced Grant Shapps less than a week after she had been forced to resign from the same job.
Only just over a week ago, in a major breach of the ministerial code, Ms Braverman admitted she had been sent an official document from her personal email to a fellow MP.
But Ms Braverman did not leave Ms Truss's Cabinet quietly, penning a scathing resignation letter in which she raised concerns about "the direction of [the] government" and said "key pledges promised to voters" had been broken.
In his speech, Mr Sunak pledged to bring “integrity and accountability” to office of Prime Minister - but, with this appointment, that does not seem to have lasted for long.
Remember too that the new Prime Minister defended Mr Johnson throughout the Partygate scandal - and was even himself given a fixed penalty notice by the Metropolitan Police.
Fortunately for Mr Sunak, the Conservative Party is currently in such mess that his fine had no bearing at all on him being installed at the head of the UK government.
Indeed, in the end, it was remarkably straightforward.
On Monday afternoon, Penny Mordaunt withdrew her candidacy despite her supporters earlier that day stating she was closing in on the backing of 100 MPs, as required by the rules to make it to the members' ballot.
In the previous contest, Ms Mordaunt had attracted as many as 105 MPs' votes - but, this time during a much shorter campaign, she gained far less traction.
Earlier, on Sunday night, former Prime Minister Mr Johnson pulled out of the running despite claiming to have enough support to be considered by the membership.
The second Conservative leadership contest since July therefore concluded without an opponent to Mr Sunak.
Still, the 42-year-old does not exactly have much of a mandate in the country at large, securing his position solely on the strength of the confirmed backing of 197 MPs.
However, Mr Sunak has resisted calls so far from all of the opposition parties to call a General Election.
This is perhaps unsurprising given the Tories' current standing in the polls which have shown them to be trailing Labour by huge margins.
Mr Sunak will hope that, by framing himself as a safe pair of hands with the economy, he can make at least a dent in the type of leads not enjoyed by Labour since the early days of Tony Blair.
Undoubtedly mind, current polling showing Labour on more than 50% is a reflection of the temporary withdrawal of support by traditional Conservative voters in the Truss administration - and not necessarily a sudden massive swathe of excitement at the prospect of a government led by Sir Keir Starmer.
In fact, it should be noted that no single party has gained an actual majority (i.e. more than 50%) of the votes cast at a General Election since the Conservatives in 1931.
Nevertheless, Labour is in its strongest position in years politically - and, with Mr Sunak warning of difficult days ahead economically, an already exhausted UK public is unlikely to take too well to further tax rises and spending cuts.
Certainly, the narrative now is different to when austerity measures were brought in by David Cameron's coalition government.
Back then, austerity was successfully framed as a necessary evil to reduce the deficit and bring down government debt - and, even then, the government increased the Personal Tax Allowance from £6,475 in 2010/11 to £10,600 in 2015/16.
By contrast, with inflation rampant, Mr Sunak is unable to produce a similar boon - and, as such, this next period should remain a favourable time for Labour, politically at least.
Economically, though, there is already some concern on the Opposition benches.
Labour - if it wins the next election - is unlikely to find anything other than a difficult situation bequeathed to them, and therefore will find it difficult to do anything too radical.
Now, Ms Truss's plans were the reckless wet dreams of Brexiteer libertarians living in a unreal world of only sunlit uplands - but, in their own way, the proposals were pretty radical.
Nevertheless, a plan of cutting taxes and increasing spending at a time of uncomfortably high inflation was always going to bring only one reaction from the financial sector.
Yet, at the same time, is not something of a concern that it was effectively the markets which determined the fate of a Prime Minister?
After all, it must be queried if, even with a significant electoral mandate from the public, the mere suggestion by a Labour government of a modest attempt of income redistribution and a bit of spending would cause the same sort of financial turmoil.
Living in a society in which any type of government can only operate within an extremely narrow orthodoxy would demonstrate a clear schism between the concepts of capitalism and democracy.
And, with tough times ahead on the back of a decade of tough times, perhaps this social contract has already been broken.
| THE SUNAK CABINET | Elected | Constituency | Department |
| Rishi Sunak | 2015 | Richmond (Yorks) | Prime Minister |
| Jeremy Hunt | 2005 | South West Surrey | Chancellor of the Exchequer |
| James Cleverly | 2015 | Braintree | Foreign Office |
| Suella Braverman | 2015 | Fareham | Home Office |
| Steve Barclay | 2010 | North East Cambridgeshire | Health |
| Gillian Keegan | 2017 | Chichester | Education |
| Ben Wallace | 2005 | Wyre and Preston North | Defence |
| Mel Stride | 2010 | Central Devon | Work and Pensions |
| Dominic Raab | 2010 | Esher and Walton | Justice | Deputy Prime Minister |
| Michael Gove | 2005 | Surrey Heath | Levelling Up, Housing, Communities |
| Kemi Badenoch | 2017 | Saffron Walden | International Trade |
| Grant Shapps | 2005 | Welwyn Hatfield | Business, Energy, Industrial Strategy |
| Therese Coffey | 2010 | Suffolk Coastal | Environment, Food, Rural Affairs |
| Mark Harper | 2005 | Forest of Dean | Transport |
| Chris Heaton-Harris | 2010 | Daventry | Northern Ireland |
| Alister Jack | 2017 | Dumfries and Galloway | Scotland |
| David TC Davies | 2005 | Monmouth | Wales |
| Michelle Donelan | 2015 | Chippenham | Digital, Culture, Media and Sport |
| Lord Nicholas True | - | - | Leader of the House of Lords |
| Penny Mordaunt | 2010 | Portsmouth North | Leader of the House of Commons |
| Oliver Dowden | 2015 | Hertsmere | Chancellor of the Duchy of Lancaster |
| Nadhim Zahawi | 2010 | Stratford-on-Avon | Party Chairman |
