1 · Counting the places
We use the Food Standards Agency's Food Hygiene Rating Scheme open data. Every food business in England has to register with its council and gets inspected, so this is the closest thing to an official list. We take the category “Restaurant/Cafe/Canteen” for all 33 London authorities (32 boroughs + the City of London).
- Restaurant/Cafe/Canteen records—
- minus likely canteens (name filter)—
- Places we count by default—
- Takeaway/sandwich shops (toggle)—
- Pubs/bars/nightclubs (toggle)—
We sanity-checked the total against OpenStreetMap, which has ~16k London cafés and restaurants mapped (volunteer mapping is patchier, so it's lower). The FSA doesn't split cafés from restaurants, so “cafés only” / “restaurants only” use OpenStreetMap's mix (— cafés) as an estimate.
2 · The canteen problem
The FSA lumps school dining halls, office canteens and hospital cafés in with restaurants. We strip records whose name contains words like school, academy, nursery, hospital, care home, staff, canteen, prison, or the name of a big contract caterer (Sodexo, Aramark, BaxterStorey…). That removes — records.
It's a blunt tool: plenty of canteens have innocent names and stay in, and a few real restaurants with “Canteen” in their name get thrown out. Treat the total as ±5%. Flip “Keep canteens” to undo the filter.
Full keyword list
3 · The maths
Plain version: count the places, count the new places you get to each year, divide.
years = placesnew visits per year
new visits per year = visits/week × 52.18 (or visits/month × 12) × the share of outings that are somewhere new (100% if you never revisit).
With “London keeps changing”: it becomes a chase. New places keep opening while you eat. If you can't eat out faster than London opens new places, you never finish. That's the ∞ screen. With realistic churn, you'd need to eat somewhere new about — times a week just to keep up.
Show the formula
Each year about o × places brand-new spots open. Unvisited places close at rate c (closures of places you've already ticked off don't matter). Your to-do list U changes like this:
dU/dt = o·N − v − c·U
Solving for when U hits zero:
years = ln(1 + c·N ⁄ (v − o·N)) ⁄ c
If v ≤ o·N, there's no solution: that's the ∞ screen.
4 · Churn: where the rates come from
There's no official opening/closing rate for London restaurants, so we use the ONS Business demography 2024: across UK food and accommodation businesses, — opened and — closed that year. It's a ballpark, so you can change both sliders.
5 · Honest caveats
- One record = one registered food business at one address. Chains count once per branch (yes, every Pret).
- Places inside other businesses (a café in a museum or a department store) usually count if they're registered separately.
- The register lags real life by weeks to months.
- We assume a year has 52.18 weeks and you never get bored, ill or broke.