The Richmond MP said that borrowing more money to fund policy but expecting future generations to pay it back is “immoral” because the cash is “not the state’s money”.
Speaking at Conservative Party conference at lunchtime, Mr Sunak acknowledged that “tax rises are unpopular, some will even say un-Conservative” but added: “I’ll tell you what is un-Conservative: unfunded pledges; reckless borrowing; and soaring debt.
“Anyone who tells you that you can borrow more today and tomorrow will simply sort itself out just doesn’t care about the future.
“Yes, I want tax cuts. But in order to do that, our public finances must be put back on a sustainable footing.”
The headline speech at the party’s first in person conference since the first lockdown comes after 18 months of increased pandemic spending from the Treasury, but Mr Sunak took the opportunity to express his faith in “fiscal responsibility.”
He told the packed conference hall: “I believe that mindless ideology is dangerous. I’m a pragmatist. I care about what works, not about the purity of any dogma.
“I believe in fiscal responsibility. Just borrowing more money and stacking up bills for future generations to pay is not just economically irresponsible, it is immoral.
“Because it’s not the state’s money, it’s your money.
“I believe that the only sustainable route out of poverty comes from having a good job. It’s not just the pounds it puts in your pocket, it’s the sense of worth and self-confidence it gives you.”
The Chancellor’s appearance on the main stage at Conservative Party conference is the first session of the event so far that has seen the main auditorium filled and delegates queueing outside.
The speech was light on policy however, with more expected to be said in the upcoming Budget and Spending Review at the end of this month.
On an early-Wednesday morning visit, Mr Sunak made jokes with the Prime Minister Boris Johnson about levelling up while they visited a construction site for Northern Powerhouse Rail.
They were shown blueprints for the project while being talked through the upgrades by Network Rail bosses on Monday.
Following the briefing, the pair, wearing hi-vis jackets, were taken on a trip up to the tracks to see the overhaul first hand.
Told that the planned six trains an hour between Manchester and Leeds will mean a more frequent service than on London Underground’s Metropolitan Line, Mr Johnson, a former mayor of the capital, replied: “That’s not saying much.”
They went on to crack jokes as they met apprentices who are helping to dig the project at the Miles Platting site.