[pveierland]

They have 1.5k public repositories here at least: https://github.com/orgs/alphagov/repositories?type=all

Collection of RFCs: https://github.com/alphagov/govuk-rfcs

Open design system: https://design-system.service.gov.uk

[WickyNilliams]

And individual departments can/do have their own GitHub org. Eg the Office of National Statistics. Some work I did ~10 years ago can be found there! https://github.com/onsdigital

[Digit-Al]

Next thing we need is for them to host their own Git infra, to avoid dependency on US Github.

[tjwebbnorfolk]

Lol remind me who owns Github again?

[pveierland]

Why do you think this is substantial? The software built in these repos is not tied to GitHub.

Git is decentralized and using a self-hosted instance of Gitea / Forgejo will give you a replacement for the essential parts of GitHub. GitHub is absolutely replaceable.