How to write a letter of support for a planning application

A letter of support for a planning application only helps if it addresses the planning merits. Here is what to say, which policies to cite, and what to leave out.

Why support letters are usually ignored

Most letters of support say the applicant is a nice family who need the space. Personal circumstances and need are not material considerations for a householder application, so those letters go in the file and change nothing. A support letter that says why the proposal complies with policy, and answers the objection an officer is likely to raise, can change the report.

What to include

• Character. Compare the proposal to what already exists on the street: "Numbers 31, 33 and 43 already have single storey rear extensions of similar depth". Established pattern is the strongest support argument there is.
• Visibility. If it is at the rear and not visible from the street, say so: the street scene is unaffected.
• Amenity. If you are the adjoining neighbour and are not harmed, say that in terms: no window faces you, the depth is modest, the garden is deep. A neighbour's non-objection is valuable precisely because the officer would otherwise assume harm.
• Policy. Name the design policy and the amenity policy in the local plan and say the proposal accords with them. In England, national policy on well-designed places supports proposals that respond to their context.
• Benefit. Making better use of an existing home, energy improvements, replacing a poor building with a better one.
• Conditions. Suggest a materials-matching condition if it would settle the only reasonable concern.

What to leave out

The applicant's need, their family situation, how long they have lived there, and how much work they have put into the house. All true, all irrelevant. Also leave out anything about the objectors.

Applicants: get your neighbours to write the right letter

If you are the applicant, do not draft a letter for neighbours to sign; officers can tell. Point them to Curtilage with the reference and let them write in their own words. The tool grounds the support in the adopted policies and keeps the personal material out, which is what makes it count.

Updated 2026-09-14. Curtilage is not legal advice.