Case Law Finder

# CASELAW-FINDER-SPEC

**Tool:** `caselaw-finder.html` · GMIAU Shell · Knowledge section
**Status:** v0.1 (2026-05-22)
**One-liner:** Enter a court + year + number (or paste a neutral citation) and get the
correct deep links to the same judgment on **Find Case Law** (The National Archives),
**BAILII**, and **Tribunals Decisions**, built-only, fully offline, nothing fetched.

---

## 1. Purpose & scope

Immigration caseworkers cite authorities by neutral citation (`[2020] UKUT 46 (IAC)`).
Each of the three free public sources lays its URLs out differently. This tool turns one
citation into the three canonical URLs so you can open the judgment without hand-building
paths or searching.

**Build-only.** The tool never fetches anything: a `file://` page can't (CORS), and BAILII
bot-walls automated requests anyway (see the retired Case Collector finding). It constructs
candidate URLs from known conventions and gives Open / Copy buttons. A built link that 404s
means that court isn't hosted by that service, not a tool bug.

Coverage is **immigration-focused**, not comprehensive UK. Courts below the supported set
(EWCA Crim, EWHC KB/Ch/Fam, UKUT AAC/LC/TCC, EWCOP, NI, Scotland) are out of scope for v0.1.

## 2. Inputs

Two interchangeable input modes, both feeding the same three fields:

| Field | Control | Notes |
|---------|--------------------|-------|
| Court | dropdown (`<select>`) | one of the §3 registry IDs |
| Year | number / text | 4 digits, `1990`–current year+1 |
| Number | number / text | the neutral-citation number (NOT a BAILII sequential id) |

**Citation paste box**, paste `[2020] UKUT 46 (IAC)` (brackets optional) or a Tribunals
Decisions slug `2018-ukut-430`; the parser (§4) fills Court/Year/Number and re-renders.

## 3. Court registry (the single source of truth)

Each court maps to a builder per service. A builder returns a URL **or** `null`
("not hosted here" shown as a muted dash, never a fabricated link).

| ID | Label | Citation form | National Archives | BAILII | Tribunals Decisions |
|---------------|----------------|------------------------|--------------------------|-------------------------------------|------------------------------|
| `uksc` | UK Supreme Court | `[Y] UKSC N` | `/uksc/Y/N` | `/uk/cases/UKSC/Y/N.html` |, |
| `ukpc` | Privy Council | `[Y] UKPC N` | `/ukpc/Y/N` | `/uk/cases/UKPC/Y/N.html` |, |
| `ewca-civ` | Court of Appeal (Civil) | `[Y] EWCA Civ N` | `/ewca/civ/Y/N` | `/ew/cases/EWCA/Civ/Y/N.html` |, |
| `ewhc-admin` | High Court (Administrative) | `[Y] EWHC N (Admin)` | `/ewhc/admin/Y/N` | `/ew/cases/EWHC/Admin/Y/N.html` |, |
| `ukut-iac` | Upper Tribunal (IAC) | `[Y] UKUT N (IAC)` | `/ukut/iac/Y/N` | `/uk/cases/UKUT/IAC/Y/N.html` | `/utiac/Y-ukut-N` |
| `cjeu` | CJEU | (case no., e.g. `C-66/16`) |, | search portal |: **search mode** (§5) |
| `ecthr` | ECtHR | (application no.) |, | search portal |: **search mode** (§5) |

Bases:
- National Archives: `https://caselaw.nationalarchives.gov.uk`
- BAILII: `https://www.bailii.org`
- Tribunals Decisions: `https://tribunalsdecisions.service.gov.uk`

**Excluded on purpose:** FtT(IAC), reported FtT determinations have no stable public
deep-link home (largely unreported; Tribunals Decisions hosts the *Upper* Tribunal). Adding
it would only emit dead links. Revisit if a stable pattern emerges.

## 4. Citation parser

Case-insensitive, whitespace-tolerant. First matching rule wins; on no match, leave fields
untouched and show a hint.

```
[Y] UKSC N uksc
[Y] UKPC N ukpc
[Y] EWCA Civ N ewca-civ
[Y] EWHC N (Admin) ewhc-admin
[Y] UKUT N (IAC) ukut-iac
Y-ukut-N (slug) ukut-iac
```

`Y` = 4-digit year, `N` = digits. Square brackets optional. The `(IAC)`/`(Admin)`
qualifier is required to disambiguate UKUT/EWHC from sibling chambers/divisions.

## 5. Search-mode courts (CJEU / ECtHR)

Their identifiers (CJEU `C-66/16`; ECtHR application numbers) don't fit court/year/number,
so these two emit **prefilled search links** on the authoritative portal instead of deep links:

- CJEU `https://curia.europa.eu/juris/liste.jsf?num=<input>` (+ a BAILII EUECJ search link)
- ECtHR HUDOC search `https://hudoc.echr.coe.int/eng#{"fulltext":["<input>"]}` (URL-encoded)

In search mode the "Number" field becomes a free-text "Case / application no." box and the
Year field is hidden.

## 6. Output

One result card per service (NA, BAILII, Tribunals Decisions), each with:
- the built URL (monospace, copy button),
- an **Open** button (`target="_blank" rel="noopener"`),
- or a muted ", not hosted on this service" line when the builder returns `null`.

Plus a **reconstructed neutral citation** line at the top (copyable), formatted per §3.

## 7. GMIAU Shell conformance

- Header ` Case Law Finder` title + ` Index` back-link (`../index.html`, `data-index-link`).
- Tabs in canonical order: Guide · Finder · Config · Settings. Per STYLE-GUIDE
 §2B the **Finder** (primary tool tab) is default-active even though Guide is listed first
 (`window.IFYI_PRIMARY_TAB = 'finder'`). Guide + Config hidden via the shared
 `ifyi_hide_guide_tab` / `ifyi_hide_config_tab` keys (both §2C CSS hooks present).
- **Config tab** holds tool-local prefs (all `localStorage`, per browser):
 - `ifyi_caselaw_default_court`, which court the Finder dropdown starts on (Upper
 Tribunal (IAC) is the immigration default).
 - `ifyi_caselaw_src_na` / `_bailii` / `_td`, per-source show/hide; hidden sources are
 dropped from the results. The CJEU/ECtHR official portal row is always shown.
- `@@IFYI_THEME@@` + `@@IFYI_SETTINGS@@` sentinels; both canonical themes
 (GMIAU Light / GMIAU Dark); mandatory themed scrollbars; §4A full-width panels.
- `@@SPEC:CASELAW-FINDER-SPEC@@` sentinel in a Guide `<details>` so the built tool carries
 this spec.

## 8. Privacy

No case data touches the tool, only public court identifiers. Nothing leaves the browser;
no network calls. Safe to ship in the public Codeberg Pages suite (tools.immigration.fyi).

## 9. Test fixtures

`gmiau-testing/caselaw-finder/cases.json`, citation expected three URLs, covering each
registry court + a Tribunals-Decisions slug parse + a search-mode court.