Boris Johnson has promised to spend billions of pounds to rescue the economy as he warned the country faces the looming “thunderclap of economic consequences” of Covid-19. The prime minister tweeted: “We want to build our way back to health. “If covid was a lightning flash, we’re about to have the thunderclap of the economic consequences. We’re going to be ready.” In an earlier interview with the Mail on Sunday he recommitted to his general election promise of a “levelling up” agenda, saying new schools, hospitals and homes would be built, infrastructure projects completed and employment created for people whose “old jobs” would not be there any more. Rejecting the former prime minister David Cameron’s austerity policies during the last recession, he said: “We are absolutely not going back to the austerity of 10 years ago.” Johnson is to unveil his plans for the economy in a speech in the Midlands on Tuesday, amid warnings of significant unemployment this autumn following the lockdown. The number of people out of work and claiming work-related benefits in the UK jumped 23% to 2.8 million in May. A new taskforce, “Project Speed”, will be led by the chancellor, Rishi Sunak, and is intended to deliver key projects faster. One of the first announcements is a number of new prisons. Johnson also claimed he was “fit as a butcher’s dog” following his own experience of coronavirus where he was in intensive care. He said he was back to his pre-illness 6.30am runs and was photographed doing press-ups in his office. He told the Mail on Sunday: “We’re going to need a very committed, dynamic plan. Not just for infrastructure, not just for investment, but making sure that young people have the confidence they need that we are going to help them get into a place of work, to keep their skills up, to keep learning on the job and get a highly paid, highly skilled job that will stand them in good stead for a long time to come. “We are going to have plans for work placements, supporting young people in jobs, apprenticeships, getting people into the workplace, making sure that their skills don’t just fall into disuse and we’re going to give an opportunity guarantee for all young people.” The home secretary, Priti Patel, said the prime minister’s investment plan would provide money for broadband connections and new roads. She told Sky News’s Sophy Ridge on Sunday programme: “As we move out of this awful period of coronavirus, this dreadful disease, we want to get Britain moving again. “We’re building now very much a road to recovery, a road map focusing on infrastructure right now, levelling up across the country, focusing on roads, broadband – the type of things that effectively help to create jobs but also provide services and economic growth and opportunity across the country.” Ministers unveiled plans on Sunday to build more prisons and have not ruled out handing them over to private operators. The Ministry of Justice said work was under way to identify locations for three new prisons, one in the north-west of England and two in the south-east. The government has previously announced plans to build a new prison near the existing HMP Full Sutton site in east Yorkshire. It is the government’s intention that at least one prison will be operated by the public sector, but it left open the possibility of others being run by the private sector. The prisons and probation minister, Lucy Frazer, said: “As well as a boost to our justice system, these prisons will create thousands of new jobs and send a clear signal that the government can and will continue to invest in the vital infrastructure this country needs.” Johnson last year pledged to build 10,000 new prison places. In addition to the new prisons announced on Sunday, construction of a jail at Wellingborough in Northamptonshire continues and early works have started at Glen Parva in Leicestershire.