Britain's written constitution?

Look at this: "Chapter 6: Elections and Government formation (DRAFT)". 

A more self-effacing title it would be hard to imagine. But read it, and you'll see that this document amounts, more or less, to a written constitution for the United Kingdom. 

All of a sudden, Britain's famously unwritten constitution has been written down - penned quietly, without political debate or public consultation, by a single, unelected official, Cabinet Secretary Sir Gus O'Donnell.

Nothing much has changed, and nobody much has noticed. A very British revolution.