Part L 2021 for dwellings now requires photographic evidence to be provided for key construction details and building services. The requirement has been introduced as part of the drive to decrease the 'performance gap', the difference between the amount of energy new homes are predicted to use, and how much they actually use.
Under Part L the contractor is now responsible for providing photographs, which must be given to the SAP assessor, Building Control Officer, and building owner. The photographs will need to show thermal continuity and quality of insulation for locations such as the ground floor, walls, roofs and windows. In addition, photos will be required for building services such as air source heat pumps and mechanical ventilation systems.
Resolution Energy has produced a useful guide summarising the requirements, you can access a copy here.