Over the past couple of months, the Money Advice Service has taken the approach of coding in the open, by using public github repositories. As a reasonably large organisation using open source software, I think opening up the code has big benefits. People get to poke around under the hood, and might even be able to get something from it. All the projects are licensed under MIT, so are free for everyone to use & abuse. They may even get some pull requests from anyone feeling particularly generous. Who knows.
It's particularly pleasing to see this attitude coming from another government organisation, and well worth a look.