TL;DR
We took every Greater London street with at least five sales since 2016 (190,000+ recorded transactions), tagged each property postcode against the full HM Land Registry / planning.data.gov.uk constraint catalogue, and computed a weighted friction score per street.
The top 10 by friction:
Every property on these streets sits inside the Central Activities Zone, an Article 4 direction, the Southwark Air Quality Management Area, and an Archaeological Priority Area — often plus a conservation area on top. Submit any householder application here and you are arguing against four overlapping policy regimes from day one.
What "friction" means
Planning friction is real, measurable, and asymmetric — two identical Victorian terraces 200 metres apart can have radically different chances of getting a loft conversion through, purely because one falls inside a conservation area boundary and the other doesn't.
We score each postcode by adding up which statutory designation polygons contain its centroid. Higher-impact designations score more:
A street's friction is the average across its postcodes. A score of 0 means no statutory layer applies (full permitted development rights, in principle). A score above 15 means a property typically sits inside four-plus overlapping designations.
For reference: the median London postcode in our analysis scores about 6. Outer London suburbs (Bexley, Havering, parts of Hillingdon) score 0–2. The streets on this list all score 17 or higher.
Methodology
Caveats: this measures *statutory designation overlap*, not the probability a specific application will be refused — that depends on the application itself. We're also measuring postcode-centroid containment, not address-level. A property at the edge of a conservation area might be inside it while a neighbour 30 metres away isn't. Always verify on the planning portal before you offer.
Top 50 — full table
Top 20 visualised
A horizontal bar chart of friction scores for the top 20:
```
Brigade Mews ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 23.0
Triptych Place ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 23.0
Maidstone Bldgs Mws ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 23.0
Oxford Drive ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 23.0
Hatfields ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 23.0
Sawyer Street ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 23.0
Vine Yard ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 23.0
Borough High Street ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 22.6
Stoney Street ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 21.7
Bermondsey Street ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 21.3
St Georges Circus ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 20.5
Marshalsea Road ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 20.4
Park Street ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 20.4
Morocco Street ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 20.3
Maltings Place ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 20.0
Windsor Street ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 20.0
Snowsfields ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 20.0
Bermondsey Square ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 20.0
New Globe Walk ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 20.0
Salisbury Road ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 20.0
```
Two distinct stories
The list is dominated by two geographies, and they tell completely different stories.
SE1 and SE11/SE17 — Borough, Bankside, Bermondsey, Elephant. Every postcode here sits inside the Greater London Authority's Central Activities Zone (which strips a swathe of permitted-development rights for office-to-residential and similar), then layers a borough-wide Article 4 direction on top, then the Southwark AQMA, then a dense weave of conservation areas (Borough High Street, Bankside, Bermondsey Street, Liberty of the Mint, etc.), then archaeological priority because the whole area sits on top of medieval and Roman London. The Globe, Borough Market and London Bridge anchor the heritage interest. The result: even tiny mews and side streets carry four to five overlapping designations.
UB8 — Old Uxbridge / Windsor Street. A completely different mechanism. Hillingdon Council has imposed five borough-wide Article 4 directions — covering HMOs, residential extensions, employment-area housing conversions, dwellinghouse construction in employment areas, and changes of use from commercial. Add the Hillingdon AQMA and the Old Uxbridge / Windsor Street conservation area on top and you've got Outer-London streets carrying the same friction load as central Southwark.
These two patterns matter. The Southwark cluster reflects *historic value* — you can't tear down a Tudor pub or build over Roman foundations. The Hillingdon cluster reflects *policy choice* — the council has decided to actively manage what would otherwise be permitted development.
What this means if you're buying
A buyer's checklist for any property on or near these streets:
Outcode-level dossiers for each of the top-10 streets' postcode areas:
What this means if you own
If you already own on one of these streets and you've been told an extension is "probably fine because the next-door neighbour got one":
The single best free check is to plot your postcode on planning.data.gov.uk and overlay every dataset. If you'd rather have it summarised in plain English: our paid £14.95 property report lists every statutory designation containing the address with the polygon name, organisation, and policy reference.
Caveats and limitations
Three things this analysis doesn't capture:
Listed buildings. A Grade I or Grade II* listing on the property itself is the most consequential designation a buyer can encounter. We hold all 382,193 English listings but they're property-level, not postcode-level. Top-50 friction score therefore *understates* the difficulty on any street where a high proportion of properties carry an individual listing — large parts of Bermondsey Street, for example, are individually Grade II listed and that's not in the friction figure.
Tree Preservation Orders. We score the presence of a TPZ in the postcode at +1 but the orders themselves are property-specific. Felling or pruning a single tree under a TPO requires a separate consent process.
Greater London Authority sub-zones. The CAZ contains office-priority areas, hotel-priority areas, and specific protected views from Greenwich Park, Primrose Hill, and Alexandra Palace. We treat these as binary inside-or-out — in practice they ratchet restrictions further within the CAZ.