What we hold

Public bodies in Britain's electricity system publish files that they then overwrite: a register replaced twice a week, a forecast replaced monthly, a page edited in place. Once replaced, the earlier copy is usually gone, and a question like “what did the register say on that date” cannot be answered from the publisher. Since 15/09/2026 an unattended job has fetched each resource below every day and kept every copy whose bytes differed from the one held, named by its SHA-256. Manifests from 15/09/2026 to 08/10/2026: 29 resources, 3336 distinct files, 1.4 GB.

What is public, and what is not. Each day's manifest, one line per artefact with the publisher's URL, the digest and the day the bytes were first seen, is committed to the repository with its OpenTimestamps proof and two RFC 3161 timestamps, freetsa.org and DigiCert, taken the same day (data/manifests). The artefacts themselves are held privately, under their publishers' terms. A copy of any artefact, as held, is available against its digest: write with the resource, the day and the digest from the manifest.

What this page never claims. A new file means the bytes differed; it says nothing about why, or whether the publisher calls it a new version. A day without a new file means the bytes matched, not that the publisher published nothing elsewhere. Days are the capture's days, in UTC. Where a publisher's metadata said a file was unchanged, the file was not fetched that day and the metadata is held instead. The archive began on different days for different resources and has gaps where a fetch failed; the manifests say which.