How this archive is built

The source

The Register of Worker and Temporary Worker licensed sponsors is published by the UK Home Office. It lists organisations licensed to sponsor workers, the routes they are licensed for, and their sponsorship rating. It is republished on most working days, sometimes more than once in a day.

Crucially, the publisher keeps no public archive. Each republication replaces the last. The register therefore answers "who is licensed today" and cannot answer "what changed" or "since when".

Licence status of the source data: Open Government Licence v3.0 (ASSUMED — confirmation requested). We have written to the publisher for explicit confirmation and will update this line with their response.

Capture

1. A scheduled job resolves the current file through the publisher's own content API, so a renamed or re-dated file is always followed correctly.
2. The file is downloaded whole and stored unmodified, append-only. Nothing is ever overwritten or deleted.
3. A SHA-256 hash and a manifest recording the source URL, the publisher's stated update time, the byte length and the capture time are stored alongside it.
4. A sanity gate checks the row count against the previous capture. A file that moves more than a set threshold is stored but withheld from publication until a human has looked at it, because that pattern means a format change at the source far more often than it means a real event.

Archive to date: 1 snapshot, 2 August 2026 to 2 August 2026.

Identifying organisations

The register publishes no company number or identifier — only a name, a town, a county, a licence type and a route. We therefore key each organisation on its normalised name and town: case, punctuation, accents and trailing legal-form words such as "Limited" or "Ltd" are set aside for matching, and trading names given after a "t/a" marker are recorded separately.

This is the best any consumer of this file can do, and it has a real consequence: if the publisher spells a name differently between two releases, we may read it as one organisation leaving and another arriving. Where the evidence is unambiguous — same town, near-identical name, exactly one candidate on each side — we pair them and record a name change instead. Where it is ambiguous, we refuse to guess and record both events separately.

Detecting changes

Each capture is compared with the one before it. We record six kinds of change: an organisation first appearing, an organisation no longer appearing, a route added, a route no longer listed, a rating changed, and a listed name changed.

What we will not say. An organisation disappearing from the register can mean a licence was surrendered, allowed to lapse, or ended in some other way; it can mean a merger or a change of registered name; it can mean a data correction at the source. We do not know which, and we do not speculate. Our language for this event is fixed:

No longer appears on the Register of Licensed Sponsors as of [date].

That sentence is generated by a single shared function used everywhere on the site, so it cannot be varied by accident.

"First observed" is not "joined"

Organisations already on the register when our archive opened on 2 August 2026 are recorded as listed on or before that date, never as having been added on it. We have no observation of what happened before we started watching and we do not present a start date we cannot support.

Organisations that appear for the first time after that date carry a real first-seen date, derived from our own comparison.

Matching to Companies House

The sponsor register publishes no company number, so we match each listing to the free Companies House bulk company dataset on registered name and location. Legal forms ("Limited", "Ltd", "PLC") and trading names given after a "t/a" marker are set aside on both sides before comparison.

A match is only shown when the evidence supports it:

• Registered names must agree once normalised. Similar is not enough.
• Location must corroborate — the same town, or failing that the same county.
• Where two or more companies fit equally well, we show no match at all rather than pick one.
• A dissolved company is not matched to a currently listed sponsor, because it is far more likely to be a namesake.

74,194 of 126,915 records are matched. The rest are unmatched, and that is a real answer rather than a gap: many sponsors are schools, NHS trusts, universities, charities, partnerships or sole traders that are not registered companies at all. Where a match is shown, the company number is linked so you can check it against the source in one click.

Companies House source: BasicCompanyData-2026-08-01.zip, published under the Open Government Licence v3.0.

Which records get a page

A record gets its own page only when it carries enough distinct, verifiable detail to be worth reading — a location, more than one route, a non-standard rating, a recorded change, a previous name, a real first-seen date. Records that would produce a page stating little more than a name are not published, and route-and-town indexes are only built where at least three organisations are listed.

Currently 76,144 of 126,915 records meet that bar. That proportion rises as the archive accumulates history, which is the intended behaviour: pages earn publication by acquiring facts.

Why the archive is published in waves

Publishing a hundred thousand pages at once produces a large number of pages that say very little, which serves nobody and is treated by search engines exactly as it deserves. We release in waves, strongest records first, and each wave has to prove itself before the next is released.

Corrections

We publish the register as released, including any errors it contains. Where the source is wrong, the correction has to come from the publisher — but we will record the dispute on the page and link to it. Where we are wrong, we fix it and say what changed. Request a correction.

What this site is not

SponsorArchive is independent and is not affiliated with, endorsed by, or a source of official information from any government. It publishes data and does not give immigration advice. Nothing here should be relied on in place of advice from a regulated adviser, and no page here is a statement about the conduct or standing of any organisation.