Their post about how they only use JS minimally:
https://technology.blog.gov.uk/2016/09/19/why-we-use-progres... https://news.ycombinator.com/item?id=12538144
https://technology.blog.gov.uk/2016/09/19/why-we-use-progres... https://news.ycombinator.com/item?id=12538144