Local lockdowns are failing to stop a second wave of coronavirus, experts have said. A ban on households mixing indoors was introduced in Northern Ireland on Tuesday and will apply in Scotland from Friday as the two countries diverged from England’s more light-touch approach. Scotland’s first minister, Nicola Sturgeon, said there was evidence that the ban on households mixing had helped contain rising cases in the west of Scotland but that it must now be applied across the country. It came as experts said there was little evidence that the piecemeal restrictions introduced in parts of England over the summer had worked, with the infection rate rising sharply in almost all areas where local measures had been imposed. Coronavirus cases have risen sharply across Greater Manchester in the past month – at least doubling in all but one of its 10 boroughs – despite restrictions first being imposed on 31 July. The infection rate is now above 100 cases for every 100,000 people in seven boroughs, more than triple the national average. Bolton’s infection rate has risen tenfold since the 22 August, from 18.4 cases for every 100,000 people to 187.5 in the week to 19 September despite being under the strictest measures in England for the past fortnight. Bolton’s measures include a ban on any mixing between households indoors, in private gardens or in bars, pubs or restaurants. It also has a 10pm curfew on nightlife, while restaurants, pubs and cafes are restricted to takeaway only. Officials in the town said its rate of cases had plateaued in recent days but that it was too early to say whether the measures were working, with one saying the slowdown may not reflect the underlying infection rate. In Leicester, where parts of the city and surrounding area have been under varying restrictions since 30 June, the number of positive cases fell over July but have since begun to bounce back. Its current infection rate remains stubbornly high, with 85 cases for every 100,000 people, although far below the level of 135 when it was the first area to be placed in local lockdown. “If the idea was to suppress the infections in Leicester, Greater Manchester, Blackburn and much of the north-west then it has failed. It’s not working,” said Paul Hunter, a professor in medicine at the University of East Anglia. He cited a graph used by chief medical officer Chris Whitty in the televised briefing on Monday, which showed cases rebounding in many areas where restrictions are in place. The failure of local lockdowns, Hunter said, was likely in part due to problems with the £10bn test-and-trace programme, which is failing to reach about half of all close contacts of infected people in the worst-hit areas. The measures already in place are also light-touch so their impact would be quite minor, he said, with compliance likely to be lower than it was during the full lockdown. Linda Bauld, a professor of public health at the University of Edinburgh, said the measures announced by Boris Johnson were “not as stringent as might have been expected”, adding that some measures such as the 10pm curfew on nightlife were already in place in part of the country. Dr David Strain, a senior clinical lecturer at Exeter University, also questioned the logic of the new nationwide curfew: “Closing down restaurants and pubs earlier will do little to stave the spread for as long as multiple different households can interchangeably meet up.” Eleanor Roaf, the director of public health for Trafford in Greater Manchester, said the failures of test and trace and the confusion over the rules meant it was difficult to say whether the localised restrictions had worked. The infection rate has more than doubled in Trafford from 19.4 cases for every 100,000 people to 53.7 in the past five weeks despite it being under extra measures since 31 July. Luton may be the only example where local restrictions have dramatically stopped the spread of the disease. The Bedfordshire town had one of the highest infection rates in England in late July, albeit at a time when transmission in the country was relatively low. Measures including a ban on gyms reopening and households mixing were withdrawn after a week and it was removed from the government’s “watchlist” after cases fell markedly. They have since bounced back but its infection rate remains slightly below England’s average and far lower than the worst-affected parts of the country.