Mr Sunak said the UK Government could not “just bury our heads in the sand and pretend they (the SNP) aren’t there” and insisted his government would be the most active in Scotland in decades by sending ministers north of the border more regularly and reforming the union unit within Number 10.
The comments come after Mr Sunak’s opponent Liz Truss said earlier this week she would “ignore” Nicola Sturgeon and she described the First Minister as an “attention seeker”.
Mr Sunak faced a bruising day yesterday after footage emerged of him telling party members he had been working to divert funding from “deprived urban areas” towards more prosperous towns.
But he was also given a boost with a new YouGov poll showing the majority of Britons believe he would be the best candidate to end a recession.
Tax and how to tackle the cost of living crisis amid a looming recession remains the key dividing line in the Tory leadership race.
Making his comments about Scotland, Mr Sunak said a reformed union unit would ensure “every single” government department operates UK-wide, despite key policy areas like education and health having been in the control of Holyrood since devolution in 1999.
His plan also includes bolstering the Scottish Conservatives, providing a campaign manager in every seat at Holyrood elections, as well as conducting a review of the support from the central party for Douglas Ross’s cohort.
“Nicola Sturgeon and the SNP pose an existential threat to our cherished union,” Mr Sunak said.
“Arguing that we should ignore them is dangerously complacent.
“We can’t just bury our heads in the sand and pretend they aren’t there – we need to stop them in their tracks.
“That’s exactly what I would do as prime minister – holding the SNP to account for its failings and personally ensuring that the UK Government has a laser focus on delivering for every part of our United Kingdom.”
Recent polls, Mr Sunak’s team has stressed, show he is more popular than the Foreign Secretary in Scotland.
But Ms Truss, who spent time in her childhood living in Paisley, has been described by Scottish supporters as a “child of the union”.
SNP MP Mhairi Black said Mr Sunak does not have “the faintest idea” what ordinary people are dealing with.
“Rishi Sunak is the same man who has slashed Universal Credit by over £1,000 for millions, hiked National Insurance payments and has now just admitted he wants to take public money from the areas that need it most and hand it over to the wealthier towns,” she said.
“He has made it crystal clear that he stands for just one thing, making the rich richer and the poor poorer, and people across Scotland know this.
“As the richest MP in Westminster, he doesn’t have the faintest idea what ordinary people in Scotland, and elsewhere, are facing daily during this Tory-made cost-of-living crisis as bills and food prices sky-rocket.
“Scotland hasn’t voted for the Tories for more than 50 years, yet we keep getting saddled with Tory governments and Tory prime ministers who will only ever work to widen the inequalities gap and try to block Scotland’s democratic right to choose its own future.”
Mr Sunak came under fire after footage emerged yesterday of him telling party members he had been working to divert funding from “deprived urban areas” towards more prosperous towns.
The former chancellor bragged that he had started changing public funding formulas to ensure more prosperous towns receive “the funding they deserve”.
The New Statesman magazine, which obtained video revealing Mr Sunak’s remarks, said they were made to grassroots Tories in Royal Tunbridge Wells, Kent, on July 29.
Tory figures were divided over the remarks, while Labour said it was “scandalous” that Mr Sunak was “openly boasting that he fixed the rules to funnel taxpayers’ money to rich Tory shires”.
The Sunak campaign defended the remarks, arguing he changed the Treasury’s green book setting the rules for government spending to help towns and rural areas also in need of investment.
In the video, Mr Sunak told Tory supporters: “I managed to start changing the funding formulas, to make sure areas like this are getting the funding they deserve because we inherited a bunch of formulas from Labour that shoved all the funding into deprived urban areas and that needed to be undone.
“I started the work of undoing that.”
Speaking ahead of the Tory hustings in Eastbourne last night, the former chancellor defended his comments, saying he was making the point that “deprivation exists right across our country”.
He said: “Well, I was making the point that deprivation exists right across our country and needs to be addressed.
“And that’s why we need to make sure our funding formulas recognise that. And people who need help and extra investment aren’t just limited to big urban areas. You find them in towns across the United Kingdom and in rural areas, too.
“And that was the point I was making, that our funding formulas that fail to recognise that are out of date, and they needed changing.”
The remarks from last week came as Mr Sunak tries to make up ground against Foreign Secretary Ms Truss to win the backing of party members who will choose the next prime minister.
Foreign Office minister Lord Zac Goldsmith said: “This is one of the weirdest – and dumbest – things I’ve ever heard from a politician.”
Jake Berry, chairman of the Northern Research Group of Tory MPs, said that in public Mr Sunak “claims he wants to level up the North, but here, he boasts about trying to funnel vital investment away from deprived areas”.
“He says one thing and does another – from putting up taxes to trying to block funding for our armed forces and now levelling up,” the Truss supporter said.
But Mr Sunak’s supporters rallied around him, with Conservative Tees Valley mayor Ben Houchen arguing that Boris Johnson led the party to electoral victory on a pledge to invest in areas “that have been ignored at the expense of urban cities”.