Rishi Sunak will announce a series of proposed changes to the planning system on Tuesday to encourage developers to build more homes, in a move designed to boost development in urban areas even while housebuilding slumps nationally. The prime minister and Michael Gove, the housing secretary, will announce a consultation into a package of measures aimed at making it easier for developers to get permission to build on derelict sites in England’s 20 biggest towns and cities. But while some builders have welcomed the move, others in the industry accused the government of trying to deflect from the wider slump in building prompted by Gove’s previous decision to allow local authorities to avoid stringent building targets. Sunak said in a statement: “We pledged to build the right homes in the right places – protecting our precious countryside and building more in urban areas where demand is highest. Today’s package is us delivering on that.” Gove added: “Our new brownfield presumption will tackle under delivery in our key towns and cities – where new homes are most needed to support jobs and drive growth.” Under the proposals, councils would have to approve new development on brownfield land – land which was previously developed but has fallen into disuse – unless they can offer a good reason why they cannot. Limits will also be removed on the kinds of former commercial buildings that can be turned into flats, removing restrictions on how big the building can be before a developer has to apply for planning permission. Ministers will also consult on making it easier for homeowners to extend their houses without seeking planning permission. The last idea has been tried before. The former prime minister David Cameron tried to scrap red tape for single-storey extensions of up to 8 metres long in 2012, in a move criticised as the “conservatory free for all”, but was forced into a U-turn after a backlash from his own MPs. Some housebuilders welcomed the government’s proposed changes, the consultation for which will run until 26 March. David Thomas, the chief executive of Barratt Developments, said: “We welcome any efforts to make it easier to get planning permission, particularly for brownfield regeneration, which is already naturally a more complicated and capital-intensive process.” However, others pointed out that the new construction that would be unlocked by the government’s latest package would be far smaller than the developments that have been lost because of previous changes to the planning system. In December, Gove announced councils would no longer have to abide by strict housing targets set according to predicted population growth, and could allocate less land to development to avoid changing the character of a local area. That move, which was first signalled a year earlier, has resulted in a widespread slump in proposed developments, with many councils choosing to delay, stop or reduce their local housing plans. The number of new dwellings, as calculated by the number of energy performance certificates issued, dropped 9% in 2023 compared with 2022. A spokesperson for the Home Builders Federation said: “Whilst we welcome any moves to bring land through for development more quickly, this consultation announcement will do little to tackle our housing crisis. “If we are to reverse the sharp falls in housing supply we are now seeing, we need some serious joined-up policies, not tinkering around the edges.”