Glossary
Supplementary Planning Documents in London boroughs
A document expanding on Local Plan policy. Often the source of borough-specific design guidance.
A document expanding on Local Plan policy. Often the source of borough-specific design guidance.
An SPD adds detail to policies already in the local plan. It is adopted after consultation but without independent examination, so it is a material consideration rather than part of the development plan — it can explain and illustrate policy, but it cannot introduce new policy.
The householder or residential extensions design guide is the one that decides most London extension applications: it sets the borough's expectations on depth, set-back, roof form, materials and glazing. Basements SPDs, conservation area appraisals and management plans, and shopfront guides are the other common ones.
Reading the relevant SPD before designing saves more applications than any other single step, because it tells you the numbers the officer will apply.
Significant but not decisive. Because it is not examined, an SPD cannot be applied as though it were policy. Inspectors regularly allow appeals where a council treated an SPD figure — a 3 m depth limit, a set-back dimension — as a rule rather than as guidance to be weighed against the specific context.
The authority prepares a draft, consults for a minimum period, publishes the responses and a statement of how they were addressed, and adopts it by resolution. There is no examination and no referendum, which is precisely why its weight is lower than a local plan or neighbourhood plan policy.
A worked Lambeth example of supplementary planning document (spd): with 64 conservation areas — the Clapham Common Conservation Area and the Herne Hill Conservation Area among the best known — London Borough of Lambeth (Lambeth Council) sees supplementary planning document (spd) constantly, and an Article 4 direction is in force there, so permitted development cannot be assumed. Where supplementary planning document (spd) pushes a Lambeth scheme out of permitted development, the route becomes a £548 application decided in 8 weeks rather than a £249 prior approval in 6 weeks.
| Status | Material consideration, not development plan |
|---|---|
| Examination | None |
| Can it create policy? | No — only add detail to existing policy |
| Most relevant to houses | Householder design guide |
| Weight | Significant but not decisive |
| Adopted by | Council resolution after consultation |
No. It is guidance, and treating its figures as rules is a common ground of appeal.
On the borough's planning policy pages, usually alongside the local plan.
It can inform a refusal, but it must be weighed rather than applied mechanically.
Pick a slot that suits you. No obligation and no sales pressure, just straight answers on your planning route.
