Validating Local Biodiversity Net Gain (BNG) Requirements with Mycelia

If you haven’t yet reviewed the article on national BNG validation requirements, we recommend starting there first.

Why Local Validation Matters

The national statutory requirements for BNG validation only cover a bare minimum. Many Local Planning Authorities (LPAs) include additional BNG requirements in their local validation lists, which ensures:

You receive more complete information upfront
Applicants avoid surprises at later project stages
Validation is consistent with your local policy

For example:

National rules only require applicants to submit baseline habitat information.
Local rules may require post-development information to assess habitat plans within the site boundary.

Step-by-step for reviewing local requirements

Step 1: Upload the Metric to Mycelia

Create a new case in Mycelia.
Drag and drop the applicant’s Biodiversity Metric into the case.
Mycelia will run the standard national checks first.

If the metric passes national rules but may raise local concerns, you’ll see a “Validation Info” message instead of a failure notice.

Step 2: Review Local Validation Information

In the local validation section, Mycelia highlights potential issues that do not violate national law but may conflict with local requirements.

These sub-sections are structured around common local validation list items, so you can quickly match them against your own policy.

Examples include:

On-site post-development information – e.g., planned habitat changes within the red line boundary
Off-site information – details of habitats outside the development site
Overall net gain – summary of whether the required uplift is achieved
“Red-box” errors – a roundup of flagged metric errors

If your LPA has corresponding requirements, these become validation issues. If not, you can ignore them.

Step 3: Communicate Issues to the Applicant

Mycelia provides two easy options for communicating with applicants:

Copy-to-clipboard (local only) – Copies plain-English text summarising all issues from the local validation section. You can paste this directly into an email or letter.
- Tip: Delete any points that don’t apply to your local rules before sending.
Copy-to-clipboard (all validation) – At the top of the page, a button copies both national and local validation issues in one go.

Benefits of Using Mycelia for Local Validation

Saves time by automatically flagging issues for review
Reduces manual effort when checking local validation lists
Streamlines communication with clear applicant-facing guidance

Troubleshooting

Issue: Local requirements don’t appear in Mycelia
- Check whether your LPA’s validation list has been updated recently. Mycelia structures checks around common requirements, so some local rules may not appear directly.
Issue: Too many irrelevant items in copy-to-clipboard text
- Simply remove the lines that don’t apply to your local validation list before sending.

Need further assistance? Contact us at mycelia-support@verna.earth.