As of February 2024, achieving measurable biodiversity net gain on development projects is now mandatory.

In order to measure BNG, a UK Habitat Classification survey is carried out and the habitats on site are subject to a condition assessment, this information is then input into the Biodiversity Net Gain Statutory Metric Calculation tool, which determines the baseline BNG score. Development proposal plans and planting schemes can then be used to determine the post-development BNG score and a net gain/loss can be determined.

A BNG assessment report will confirm net gain / loss, will confirm if the project is in compliance with national and local planning policy and will provide recommendations on how to progress, if net gain is not initially achieved.

The optimal survey period to undertake UK Habitat Classification surveys is between April and September inclusively however, they can be undertaken at all times of year depending on the habitats that are present on site. This survey method is used to categorise habitats and record their condition and distinctiveness against set criteria.