Ministers were warned three weeks ago that the country faced a “very large epidemic with catastrophic consequences” unless they took immediate action by imposing a two-week “circuit breaker” lockdown to reduce the spread of coronavirus. The government’s Sage committee of experts urged ministers to move urgently as new infections rose in all age groups across the country, even as the full impact of opening schools and universities had yet to be felt. The group proposed five measures including the circuit breaker – a short period of lockdown to drive new infections down – that it urged ministers to consider to head off a second wave of the virus that “would fall disproportionately on the frailest in our society, but also those on lower incomes and BAME [black, Asian and minority ethnic] communities”. The warning appeared in official documents dated 21 September that were released on Monday evening after the prime minister wrapped up a press conference at which he announced the new three-tier Covid alert system for containing the epidemic. The experts said: “As over 90% of the population remain susceptible, not acting now to reduce cases will result in a very large epidemic with catastrophic consequences in terms of direct Covid-related deaths and the ability of the health service to meet needs.” The committee said that despite the national lockdown and the establishment of a test, trace and isolate system, the epidemiological situation was such that “a package of measures is required urgently” to prevent an exponential rise in cases. As well as the circuit breaker, the group’s five recommendations included advising all who can to work from home; a ban on household mixing in homes, except for those in support bubbles; the closure of all bars, restaurants, cafes, indoor gyms and services such as hairdressers; and all university and college teaching to be online “unless absolutely essential”. Only one of the five measures has been introduced nationally – the exhortation to work from home if possible. The latest figures show that the epidemic is doubling in size every seven or eight days, but in some areas the rate is thought to be even faster. Given the pace at which the epidemic is growing, Sage estimated there could be around 3,000 hospital admissions per day by the end of October, the peak at the start of April, “unless rapid action is taken to reduce transmission”. The circuit breaker was proposed as a way to reduce R, the number of people on average that an infected person infects, to below 1, and push new infections down to a lower level. The other measures were said to be necessary to maintain R around 1 for the coming months. Careful monitoring would then be needed to ascertain whether more interventions were needed. While the experts said the circuit breaker could push the epidemic back 28 days if it was well adhered to, they said multiple circuit-breaks might be necessary to keep cases low into the winter. In light of the rapid rise in cases, the group also called for a raft of further measures to prevent transmission in care homes, hospitals and other settings, such as prisons and hostels for the homeless. The scientists stressed that all the interventions proposed would take a toll on health and wellbeing and that additional measures to mitigate the harm, and to ensure they did not hit the poorest and most vulnerable the hardest “will be needed urgently”. Taking action fast would reduce the number of deaths and the time many restrictions had to be in place, though some would be needed for months, at least over the winter, the scientists said. The document went on to deliver a damning assessment of NHS test and trace, which the committee had previously said needed to be working effectively before the national lockdown was lifted, and when schools re-opened. The experts warned that “low levels of engagement” with the system, coupled with testing delays and likely poor rates of self isolation suggested “this system is having a marginal impact on transmission at the moment”. “Unless the system grows at the same rate as the epidemic, and support is given to people to enable them to adhere to self-isolation, it is likely that the impact of test, trace and isolate will further decline in the future,” the experts added.