The UK government's digital services implement Open Standards for most of the code they develop. While this isn't something that third party vendors have to do,

The UK government's digital services implement Open Standards for most of the code they develop. While this isn't something that third party vendors have to do, GDS/PDS/MOJDS/HMRCDigital are all rapidly reducing the amount of work external vendors do for government anyway. https://github.com/alphagov https://github.com/alphagov