Biddy Baxter and Sarah Green have described how the programme was conceived.

From "The Guardian".
http://www.guardian.co.uk/tv-and-radio/2013/feb/25/how-we-made-blue-peter

Writing personally, when doing a live transmission from Lime Grove, it was quite frightening when the last notes and script changes were given to the presenters and crew as the titles were roll¡ing!