gov.uk is practically unique in been a successful public facing government development project.

The people behind it are incredibly talented, they have a blog here https://gds.blog.gov.uk/

It's almost like if you get together a talented team of people, give them a clear brief and scope and then let them use whatever tools they need you end up with a good product at the end...

Also good https://digitaltransformation.blog.gov.uk/

Also interesting https://www.gov.uk/service-manual/agile/index.html which is their manual for providing digital services.