Gyles Brandreth was the MP for Chester from 1992-97
It's something that's done by politicians of every persuasion.
They can't help themselves - they do it late at night; first thing in the morning; once a day, sometimes once a week.
It can make them famous or notorious; it can make them wealthy; it can even make them immortal. So what is it?
In the first of a new three part Sunday Supplement series, the humourist and former Tory whip Gyles Brandreth considers the insights and indiscretions which have made diaries such an entertaining and revealing form.
In Part Two, Gyles explores the essential ingredients of a successful diary.
It's not easy to write a political diary and there are plenty of risks as Gyles Brandreth explains in Part Three of 'How to write a political diary'.