The Government Says

Permitted development rights for onshore wind turbines in England

Permitted development rights for onshore wind turbines in England
Local copy of permitted-development-rights-for-onshore-wind-turbines-england.pdf

https://www.gov.uk/government/consultations/permitted-development-rights-for-onshore-wind-turbines-in-england

seen at 10:31, 18 March in Policy papers and consultations.