The housebuilders said they will co-operate with the watchdog, and Persimmon added: “A proportion of our properties were sold on a leasehold basis in the past. Following consultation with government, stakeholders and customers we took the decision to stop selling leasehold houses where Persimmon owns the land freehold in 2017. Any customers of a Persimmon leasehold property in the last six years have been given the right to buy their lease at below market value and many have done so.”