Three miles out of Padstow, PharmSee's location analyzer returns 0 GP practices and 1 pharmacy — the lowest GP count in any English town we have audited. Five miles out, the ring catches 2 GP practices and 3 pharmacies (0.67:1 ratio). Fifteen miles out, the ring catches 95 GP practices and 22 pharmacies (4.32:1 ratio).
That's a 47.5x increase in GP count between a 5-mile and a 15-mile query on the same postcode centre. No other location in PharmSee's rural atlas comes close. Padstow is a methodology problem disguised as a coastal pharmacy story, and it's the reason we are formalising the ring-contamination flag as PharmSee's third location-analyzer caveat — alongside radius-default (cycle 12) and chain-classification (cycle 14).
The raw numbers for PL28 8AE
| Radius | GP practices | Pharmacies | Ratio | What the ring catches |
|---|---|---|---|---|
| 3 mi | 0 | 1 | undefined | The single corridor pharmacy |
| 5 mi | 2 | 3 | 0.67:1 | Wadebridge & Camel Estuary practice |
| 10 mi | 77 | 5 | 15.40:1 | The entire Newquay/St Columb cluster |
| 15 mi | 95 | 22 | 4.32:1 | Bodmin, Wadebridge, Newquay, Liskeard |
The growth isn't linear. Between 3 mi and 5 mi you pick up a single new GP practice. Between 5 mi and 10 mi you pick up seventy-five more GP practices — that is a fifteenfold jump, one ring step, and it tells you something real about North Cornwall's geography: the GPs cluster inland 8-12 miles south of the coast, and Padstow sits on the far side of that cluster.
What contamination means in ratio language
A "clean" rural ring adds GPs proportionally to its area (roughly 1.8x between 5 mi and 10 mi, because the ring's area grows 4x but density is lower at the edges). When GP count instead grows 15-50x between adjacent rings, the outer ring is not measuring a single rural catchment — it is measuring the closest metropolitan cluster plus everything in between.
Here's what five rural benchmarks look like across the same 5→15 mile GP growth ratio, using PharmSee's location analyzer at standard postcode centres:
| Location | 5 mi GP | 15 mi GP | Growth factor | Ring status |
|---|---|---|---|---|
| Penzance TR18 | 5 | 17 | 3.4x | Clean — isolated peninsula |
| Bude EX23 | 1 | 5 | 5.0x | Clean — North Cornwall coast |
| Horncastle LN9 | 3 | 25 | 8.3x | Borderline — catches Louth/Skegness |
| Louth LN11 | 5 | 55 | 11.0x | Contaminated — catches Grimsby conurbation |
| Holt NR25 | 1 | 21 | 21.0x | Contaminated — catches Norwich approach |
| Padstow PL28 | 2 | 95 | 47.5x | Severe — catches Newquay + Bodmin + Liskeard |
Penzance is the clean reference: a true isolated peninsula. GP growth stays modest because Land's End is at the edge of the world. Anything above 10x is a flag that your "rural pharmacy catchment" query is actually pulling a mixed urban-rural population.
The proposed rule
From cycle 21 onward, PharmSee's rural articles should apply this test before quoting ring ratios:
If the 5→15 mile GP count growth exceeds 10x, flag the ratio as contaminated and either (a) quote only the 3-5 mile ring with a population caveat, or (b) publish both rings and label the outer one "corridor reach" rather than "catchment".
The rule follows directly from the cycle 14 two-ring rural reporting convention (5 mi → 15 mi pairs as the rural default) but adds a quantitative test for when the 15 mi figure is load-bearing.
Padstow's three Boots branches in the 5-mile ring
The three PL28 5-mile pharmacies are a Boots (FAG61, PL28 8AL), a Wadebridge-area independent, and the cycle 12 Padstow Boots branch (FA306 at PL28 8AE, flagged in an earlier PharmSee cycle as the lowest-revenue Boots branch measured in our register at ~£66,647 per year). That is the entire PharmSee retail population within a 5-mile drive of Padstow. Dropping to the 15 mi ring gives you 22 pharmacies, but 19 of them are not Padstow pharmacies — they are Newquay's and Bodmin's, and they do not serve Padstow residents in any operational sense.
What gets mis-reported without the flag
Without the ring-contamination flag, a 15-mile GP:pharmacy ratio on Padstow reads as 4.32:1 — one of the highest "under-served" ratios in PharmSee's rural atlas. That is a false positive. The ratio is high because the GP ring is catching Bodmin and Newquay while the pharmacy ring is catching the same towns with their fuller retail coverage intact. The actual Padstow pharmacy catchment is 5 pharmacies across the 10 mi ring serving a hyper-seasonal ~8,000 permanent-population corridor that swells 3-5x in summer. Pharmacy First revenue per branch is structurally constrained by seasonal labour-market friction, not by GP density.
Related PharmSee methodology
- Two-ring rural reporting convention (cycle 14)
- Chain classification caveats
- Coastal seasonal demand adjustment (cycle 19)
Try it yourself
- Benchmark pharmacies in any postcode: /app/pharmacies
- Run a location analysis with explicit radius: /app/location
Sources
- PharmSee location analyzer, PL28 8AE, 2026-04-11 queries at 3/5/10/15 mi
- PharmSee rural atlas cycles 10-20 — Lincolnshire Wolds, North Cornwall, Norfolk coast benchmarks