AnalysisCroydonAugust 2026
What Croydon actually refuses on
Transport is Croydon’s most-cited refusal category, and the first-listed reason in 31 of 483 refusals. Design is the leading primary ground.
Housing policy rests on assumptions. The record lets us test them.
Perfect Scale studies what happens when housing policy meets the planning system. We build datasets from planning decisions, use them to test questions about how the system behaves, and publish what we find.
Current finding
London does not operate one planning system for small sites.
Once differences in the applications each borough receives are accounted for, a wide gap in outcomes remains. The distance between the two ends of the distribution is 43.6 percentage points.
Borough
Outcome differential (percentage points)
Diff
Croydon
−21.8
Havering
−21.4
Lambeth
−16.8
Barking & Dagenham
−16.4
Waltham Forest
−15.3
Newham
−14.6
Hounslow
−13.1
Kingston
−10.5
Tower Hamlets
−8.8
Barnet
−8.7
Brent
−7.6
Bromley
−6.4
Harrow
−3.2
Lewisham
−1.9
Hillingdon
−1.7
Redbridge
−0.5
Greenwich
−0.4
Wandsworth
+4.0
Hackney
+7.1
Enfield
+7.3
Merton
+8.7
Islington
+11.3
Camden
+12.2
Haringey
+13.8
Westminster
+13.9
Sutton
+15.0
Kensington & Chelsea
+15.1
Ealing
+15.5
Southwark
+15.5
Hammersmith & Fulham
+16.3
Bexley
+18.9
Richmond
+21.8
−24pp−12pp0+12pp+24pp
Mix-adjusted outcome differential: each borough’s approval rate against what London-average decision behaviour would have produced on that borough’s own caseload, holding scheme type, unit count, conservation status and transport accessibility constant. 11,689 decided applications across the 32 authorities with complete covariates. Descriptive, not causal.
Evidence
The London Small Sites Dataset
Every residential planning application for one to nine homes across London’s 33 planning authorities, recorded to a common method.
14,600
applications
11,694
decisions
33
planning authorities
2023–
updated quarterly
Research
What are we trying to find out?
- Do policy thresholds change what gets proposed?
- What causes small housing schemes to be refused?
- Do design codes change what gets built?
Proposition
Policy is an experiment.
A policy is introduced because somebody expects it to change what people do. Applicants respond, officers decide, schemes proceed or fail.
Those responses leave a record. Perfect Scale uses it to test what happened.
Latest research
AnalysisLondon-wideAugust 2026
Why we cannot tell you whether pre-application advice works
A published finding on pre-application advice turned out to be measuring the way the data was collected. The retraction, and what would answer the question properly.
ResearchLondon-wideJune 2026
Given what you received: the outcome differential in London’s small-sites planning
Across 11,689 decided applications in 32 boroughs, the gap between the most permissive and most restrictive authority runs to 43.6 percentage points once caseload mix is held constant.
Questions are welcome.
If you are working on housing or planning and there is a factual question the record might help answer, get in touch.