Natural Connections Demonstration Project: https://www.gov.uk/government/news/englands-largest-outdoor-learning-project-reveals-children-more-motivated-to-learn-when-outside

The project, funded by Natural England, Defra and Historic England and delivered by Plymouth University, was the largest project of its kind in England, helping more than 40,000 primary and secondary school pupils get out of their classrooms and into the outdoors. 92 per cent of pupils involved in the project said they enjoyed their lessons more when outdoors, with 90 per cent feeling happier and healthier as a result. The project has found taking lessons outside can help motivate teachers, with 79 per cent of teachers reporting positive impacts on their teaching practice. Almost 70 per cent of teachers said that outdoor learning has had a positive impact on their job satisfaction and 72 per cent reported improved health and wellbeing.

Natural England, (2017): https://youtu.be/HJPuwDsZdRI (11.29 mins)