Mandatory biodiversity net gain (BNG) will now apply to UK nationally significant infrastructure projects (NSIPs), with greater scrutiny of how biodiversity is considered in the Development Consent Order (DCO) process.

Introduced on 2 November 2026, the mandatory regime is stricter and will require developers to consider biodiversity earlier in the process, and where gains cannot be delivered within the development, projects may need to purchase off-site biodiversity units.

Angus Walker of law firm TLT noted: “For developers entering the mandatory regime, the message is straightforward: understand the baseline early, build BNG into design, keep calculations under review and establish how the required gains will be delivered.”

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