Boris Johnson insisted there was no alternative to the coronavirus restrictions he has been forced to introduce as he promised to forge a new Britain "in the teeth of this pandemic".
The Prime Minister promised a revolution in green power generation, reforms to the social care system and improvements in education as he addressed the online Conservative Party conference.
But in the face of Tory unease about the state interventions imposed by the Government as a result of the virus, Mr Johnson insisted they were the only step he could take.
Mr Johnson said: "This Government has been forced by the pandemic into erosions of liberty that we deeply regret and to an expansion in the role of the state from lockdown enforcement to the many bailouts and subsidies that go against our instincts.
"But we accept them because there is simply no reasonable alternative."
He praised Chancellor Rishi Sunak as he sought to dispel speculation about a rift between the two over the response to the crisis.
"Rishi Sunak, the Chancellor, has come up with some brilliant expedients to help business, to protect jobs and livelihoods but, let's face it, he has done things that no Conservative chancellor would have wanted to do except in times of war or disaster."
The Prime Minister said the UK economy went into the pandemic with "chronic underlying problems" which he vowed to address.
"Long-term failure to tackle the deficit in skills, inadequate transport infrastructure, not enough homes people could afford to buy, especially young people.
"And far too many people across the whole country who felt ignored and left out, that the Government was not on their side.
"And so we can't now define the mission of this country as merely to restore normality, that isn't good enough.
"In the depths of the Second World War, when just about everything had gone wrong, the government sketched out a vision of the post-war new Jerusalem that they wanted to build, and that is what we're doing now, in the teeth of this pandemic."
The Prime Minister confirmed plans for a green energy revolution, performing a U-turn on his previous criticism of wind power.
He said the Tories would help people take their first step on the housing ladder with 95% mortgages, transforming "generation rent into generation buy".
Mr Johnson said: "We will transform the sclerotic planning system, we will make it faster and easier to build beautiful new homes without destroying the green belt or desecrating our countryside.
"But these reforms will take time and they are not enough on their own.
"We need now to take forward one of the key proposals of our manifesto of 2019: giving young, first-time buyers the chance to take out a long-term, fixed-rate mortgage of up to 95% of the value of the home, vastly reducing the size of the deposit."
He added: "We believe that this policy could create two million more owner-occupiers, the biggest expansion of home ownership since the 1980s."