What a British Defence White Paper represents

What was the 1966 Defence White Paper for viewers unfamiliar with the British system?

It was the government's formal defence-policy statement, normally reached after earlier consultative papers and then carried into parliamentary and budget decisions.

A White Paper is the government's mature statement of policy before the associated proposals proceed through parliamentary and budgetary processes. A Green Paper generally belongs to an earlier consultative stage. Defence discussions can also use a Pink Paper for an additional preliminary or special stage. The colour signals where a document sits in policy formation, though it does not guarantee that the strategy inside it is sound.