Chancellor Rishi Sunak said there would be “hard choices” to come as he attempts to balance the books following the coronavirus crisis.
Mr Sunak told the Conservative Party conference that he could not continue to “borrow our way out of a hole”.
He acknowledged that the pandemic had already forced ministers to make “difficult trade-offs and decisions” but promised the “overwhelming might of the British state” was being used to help as many people as possible.
Mr Sunak used his address to the virtual conference to praise Prime Minister Boris Johnson, following rumours about a rift between the two men, fuelled by the Prime Minister staying away from the Commons when the Chancellor unveiled his winter economy plan in September.
The Chancellor and Prime Minister visited a renewable energy firm in central London together on Monday morning ahead of the speech and Mr Sunak praised Mr Johnson for being right on the “big calls”.
But Mr Sunak warned that the UK was only “part way through” the coronavirus outbreak, which had already reached “deep into our economy and society”.
The Government has already committed more than £190 billion for people, firms and services but elements of that support – including the furlough scheme which ends this month – are now being withdrawn.
Mr Sunak said: “This Government has never been blind to the difficult trade-offs and decisions coronavirus has forced upon on us.”
The Government had “stood between the people and the danger and we always will”.
The changes to the economy cannot be ignored and no chancellor could protect every job or business, Mr Sunak said.
“The pain of knowing it only grows with each passing day,” he added.
“So, I am committing myself to a single priority – to create, support and extend opportunity to as many people as I can.
“Because even if this moment is more difficult than any you have ever faced, even if it feels like there is no hope, I am telling you that there is, and that the overwhelming might of the British state will be placed at your service.”
Ministers have already set out plans to help people retrain or acquire new skills and Mr Sunak has extended financial support schemes for firms.
Balancing the books will either require spending cuts or tax rises in the future and Mr Sunak acknowledged there would have to be action in the medium term.
“We have a sacred responsibility to future generations to leave the public finances strong, and through careful management of our economy, this Conservative Government will always balance the books,” he said.
“If instead we argue there is no limit on what we can spend, that we can simply borrow our way out of any hole, what is the point in us?
“I have never pretended there is some easy cost-free answer. Hard choices are everywhere.”
Shadow chancellor Anneliese Dodds said: “The Chancellor spoke for just 10 minutes today – and he had nothing to say to the millions of people whose jobs are now at risk because of his policies.
“Britain risks the worst unemployment crisis in decades and Rishi Sunak’s name will be all over it.”
Confederation of British Industry director-general Dame Carolyn Fairbairn said extra support should be considered for parts of the economy which were being badly hit by lockdown measures.
“Protecting our economy’s ability to recover is the best route to balancing the books,” she said.
Meanwhile, the Chancellor has defended his Eat Out to Help Out scheme which sought to encourage diners to return to restaurants and pubs with a state-backed discount.
At the weekend, Mr Johnson suggested the incentive “may have helped to spread the virus” and that its impact needed to be counteracted, with the country facing a second surge in positive Covid-19 cases.
But Mr Sunak, in an interview with The Sun ahead of his speech, said the scheme had helped prop-up two million jobs and that he had no regrets about paying for it.
Asked if he had any regrets, he replied: “No, definitely not. We had an industry that I care deeply about because of employment. It’s over two million people.”