Rishi Sunak must not unleash wave of austerity - Sturgeon
Nicola Sturgeon says public services would not stand further austerity
Rishi Sunak must not unleash a new wave of austerity on the UK, Scotland's first minister has said.
Nicola Sturgeon congratulated the former chancellor on winning the race to be prime minster, but urged him to call an early general election.
She said public services would not stand further austerity and added it was time for a "fundamental rethink".
Mr Sunak is expected to take office on Tuesday after formally meeting King Charles III.
He will become the UK's first British Asian prime minister after Commons Leader Penny Mordaunt pulled out of the Tory leadership contest.
Nearly 200 Conservative MPs publicly backed him to succeed Liz Truss, ahead of the nomination deadline on Monday.
Ms Sturgeon told BBC Scotland she would do her very best to "build a constructive working relationship" with the next prime minister.
But she said: "He absolutely should not unleash another wave of austerity. 
"Our public services, the Scottish government's budget, we're still dealing with the legacy of the first wave of Tory austerity.
"We are dealing with the problem of soaring inflation. Our public services cannot stand another round."
She added: "People, businesses, families across the country already dealing with the cost of living crisis cannot withstand this - it is time for a fundamental rethink."
Mr Sunak warned of the "profound economic challenge" ahead in his first speech after winning the Tory leadership contest.
But Scotland's first minister said the country should not be trapped in a "Tory mindset" that there was no alternative to the current "economic mayhem".
"It's been caused by Brexit and there's a real need for Rishi Sunak - who was a Brexiteer - to face up to that," she said.
"Brexit is doing the economy real damage and that's been compounded by the decisions Liz Truss took that brought the UK economy to its knees."
Challenged on how she would do things differently, Ms Sturgeon highlighted that an independent Scotland would inherit the economic position of the UK.
"Scotland is a wealthy country, we have amazing resources, not least our renewable energy," she said.
"Dealing with the fiscal situation in a humane way, in a civilised way, in a way that protects public services and gets the economy growing based on our sustainable resources is the way to do it - not another round of austerity."
Liz Truss said she would "ignore" Nicola Sturgeon as prime minister - and it was perhaps the one pledge she ended up standing by, as she never had a formal meeting or even a phone call.
Rishi Sunak may well look to reach out, but his words about Ms Sturgeon haven't been much warmer - talking about her and the SNP as an "existential threat" to the union.
Ultimately the personalities may not be what defines the relationship. There are huge policy issues looming between the two, from the best way to nurse the economy back to health to how best to support families through the cost of living crisis.
Mr Sunak has talked of running "the most active UK-wide government in decades" - something sure to wind up Scottish ministers. And all of that comes before you get to the independence referendum Ms Sturgeon has pencilled in for next October.
Regardless of how the personal relationship plays out, these two political leaders are likely to be at odds from day one.
Opposition parties have called for a general election as Mr Sunak prepares to take office as the third Conservative prime minister since the UK last went to the polls in 2019.
Mr Sunak addressed Tory MPs after the result was announced. In the speech - which took place behind closed doors - Mr Sunak ruled out an early election, MP Simon Hoare said.
However, Ms Sturgeon said: "He's the second person in a row to be appointed to the position by Tories, not elected by the population. 
"The idea that he can go two years before seeking or winning a democratic mandate is unthinkable."
She added: "He hasn't been elected, and probably wouldn't be elected in Scotland if we were given the chance.
"He's another prime minister with no democratic legitimacy in Scotland."
Watch: Rishi Sunak makes first public address since winning Tory leadership contest
Commenting on Mr Sunak's opposition to her plans for another Scottish independence referendum, Ms Sturgeon said it was for the people of Scotland to decide.
"Scottish democracy will not be the prisoner of Rishi Sunak or any British prime minister," she said.
Scottish Tory leader Douglas Ross earlier congratulated Rishi Sunak on his victory.
And Conservative MP David Mundell told BBC Radio Scotland's Drivetime that he was sure Mr Sunak would soon make a phone call to Nicola Sturgeon, unlike the current incumbent at Number 10.
MP for Dumfriesshire, Clydesdale and Tweeddale said: "I think she will hear from the prime minister, just as I think that Mark Drakeford in Wales and the leaders of Northern Ireland will.
"It's very important that the prime minister works closely with devolved administrations on areas of common interest.
"I think that we will see a constructive approach from Rishi Sunak."
Scotland's Conservative leader Douglas Ross wants his "party to unite behind PM"
Meanwhile, Scots businessman Charan Gill - who made his fortune with the Ashoka Indian restaurant chain - told Drivetime he was "very happy" to see the UK's first British Asian prime minister.
"The significance of the event today is more important to me than the politics of the situation," he said.
"Being an immigrant to this country, I came here 50-odd years ago, one of these people who thought he would never see this day.
"This is a historical milestone which I never thought we would reach"