Blue Line Boundary on a Location Plan Explained

The blue outline helps the authority understand the applicant's wider land interest without expanding the application site itself.

Evidence checked 18 August 2026 · Requirements vary by UK nation and planning authority

Red and blue have different jobs

Red defines the site being applied for. Blue shows relevant nearby ownership outside that site. Do not use blue as a second version of the red boundary.

When it is relevant

Use it where the applicant owns adjoining fields, a neighbouring plot, a separate access parcel or other nearby land that falls outside the application.

Make the colours unambiguous

Use clear contrasting lines and a key if necessary. Check the colours remain distinguishable in the exported file.

Base the blue line on ownership, not convenience

First define the red application site from the proposal. Then identify other relevant close or adjoining land in the applicant's ownership and show it separately in blue where the applicable rules require it. Do not move necessary access or operational land into blue merely to make the red site smaller.

Blue land is not development land in the application

The blue outline provides ownership context; the proposal is not being authorised on that land by virtue of the blue line. If part of it is necessary for the development, reconsider whether it belongs inside the red application site and whether the forms and ownership notices agree.

Red and blue boundary roles
BoundaryMeaningCommon mistake
RedLand to which the application relatesDrawing only around the new structure
BlueOther relevant applicant-owned land outside the siteUsing blue for land needed to access or operate the proposal

Check the ownership evidence and UK-nation rules

In England and Wales, a Land Registry title plan can help investigate registered ownership but normally shows general boundaries rather than the exact legal line. Scotland and Northern Ireland have their own land-registration and planning systems. Use the planning guidance and ownership documents applicable to the site, and take professional advice if ownership or boundaries are disputed.

Local requirements may differ. Check the current validation list for your planning authority before submitting.

Evidence checked 18 August 2026

Official sources and further reading

Planning requirements differ across the UK. The scope label on each source shows where it applies; always use the current rules for the authority receiving the application.

Questions people also ask

Is a blue line always required?

No. It is used when there is other nearby land in the applicant's ownership.

Does blue land form part of the application?

No. The application site is the land within the red line.

Do I draw blue around every property next to the site?

No. The blue line is for other relevant land in the applicant's ownership, not unrelated neighbouring land.

Can the blue line replace an ownership certificate?

No. The plan and the application form perform different jobs. Complete the correct ownership certificate and notices for every part of the red application site.

What if the applicant owns no other adjoining land?

A blue line will not normally be needed for that reason. Check the requirements for the authority and application route.

Ready to create your planning map?

Search by postcode or address, choose the scale and coverage, add your application boundary and download from UKPlanningMaps.com. For help with an unusual site, call 01856 898 022.

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