Boris Johnson has conceded there were “things we could have done differently” over Covid-19, and admitted the government did not understand the virus in the “first few weeks and months”. In a sometimes combative interview with the BBC, the prime minister repeatedly refused to discuss any lessons that could be learned before a possible second wave of Covid-19 this winter, saying it was not the moment to “run a kind of inquiry into what happened in the past”. But Johnson admitted there were “very open questions” about whether the lockdown had started too late. Recollecting that period, Johnson said “the single thing that we didn’t see at the beginning” was the extent to which coronavirus could be transmitted asymptomatically between people, meaning it had spread further than believed in the UK before the lockdown was imposed. Several of the government’s own scientific advisers have said the lockdown came too late. Prof John Edmunds, a member of the Scientific Advisory Group for Emergencies (Sage), said in June the decision “cost a lot of lives”. But the PM rejected the idea that changes in policy over lockdown, mask use and mass testing meant the government response could, as Edmunds said, be portrayed as “a story of delay that sadly cost lives”. The UK went into lockdown at the end of March. Johnson said the UK, in common with many other countries, had been taken by surprise at the extent to which coronavirus could be spread by people not showing any symptoms, and insisted the government had stuck to medical advice “like glue”. But after repeated questioning about whether better decisions could have been made, given the UK’s 45,000-plus confirmed deaths, the highest in Europe, and if some scientific advice could have been incorrect, Johnson eventually conceded errors were possible. “Maybe there were things we could have done differently, as I’ve said, and of course there will be time to understand what exactly we could have done, or done differently,” he said. “But what I think the public wants us to do now is to focus on getting the preparations ready for what, as I say, could be a resurgence of the virus this winter.” Last week, Johnson committed for the first time to holding an independent inquiry into the UK response to the pandemic, telling MPs in the Commons only that this would be “in the future”. In the BBC interview, held to mark his first year in office, Johnson stressed how hard it was to initially cope with a mass outbreak of a new virus: “I think when you look back at this crisis, everybody can see that this was something that was new, that we didn’t understand in the way that we would have liked in the first few weeks and months.” He added: “If you look at the timing of every single piece of advice that we got from our advisers, from Sage, you will find that whenever they said that we needed to take a particular step, actually, we stuck to that advice like glue,” Johnson said. He repeatedly sought to avoid discussing mistakes that could have been made, saying there would be “plenty of time by the way to look back at all the other things that we need to learn”. He added: “I think what people really want to focus on now is what are we doing to prepare for the next phase, because if I may say so, you’re talking about this as though it’s in the past and it’s not, it’s in the present.” Earlier this week the government announced the flu vaccine would be offered to everyone over 50 in England – up to 30 million people – this winter in an attempt to prevent the NHS being overwhelmed by a second wave of coronavirus. On his own experiences with coronavirus, which involved a brief stay in intensive care, Johnson highlighted his weight, and a government campaign being launched next week on obesity, seen as a risk factor for Covid-19. “That’s why we need to tackle our national struggle with obesity,” he said. “Typically our great country tends to be a little bit fatter than many other countries in Europe. So you asked about my own personal circumstances, and one of the lessons I drew from that is the need for us all to be fitter and healthier.”