Housebuilders are churning out substandard housing schemes with poor living conditions despite councils having the power to block them, according to new research.

The National Planning Policy Framework was amended in July to allow councils to refuse “development that is not well designed”. A study by University College London found that the Planning Inspectorate, which hears housebuilders’ appeals, is now three times as likely to back councils who reject developments on design grounds. But it also found that the vast majority of those blocked were in the south-east, suggesting that elsewhere councils were not using the new powers.