Sources of Information
These rate listings have been put together from a variety of sources both primary (official Post Office documents) and secondary (postal rate information compiled by philatelists and published in books or magazines). Although the former are of course the foundation for any rate tables, the latter tend to be a lot more accessible! The main sources consulted for the present site were as follows.
Acts of Parliament
Major changes to Post Office operations such as postal rates and new services originally had to be specifically authorised by an Act of Parliament, often going into significant detail. The Acts are the basic source for pre-1840 rates, and still relevant for later rates. The texts of most of the key ones up to 1901 are available in the sources section.
Treasury Warrants and Statutory Instruments
The system developed over time and eventually Acts authorised routine changes such as new postal rates to be made by warrant, which thus becomes the basic source for the charges in force. These are not yet available on the site, but this is on the to-do list.
Post Office Schemes
From 1969 onwards, the official legal announcements of changes to postal prices and services have been made in the form of "Post Office Schemes" printed in the official Government publication the London Gazette. These have been extracted from the complete editions available on the Gazette web site and can be downloaded in PDF form from the sources section.
Post Office Circular
This was the publication which kept the staff at the sharp end informed about changes to the rules and procedures. Published fortnightly on average, for the period between about 1870 and 1970 it is an absolute go-to source for settling many questions about the date a new rate was introduced. Unfortunately the full run is usually only available in The Postal Museum (TPM).
Post Office Guide (British Postal Guide until 1880)
This book outlining the postal regulations in force was published regularly for the use of the public (four times a year at first, later annually). It's an important way to check and search for rates, especially for the more obscure facilities, and as it gives a snapshot of the regulations at a point in time it makes it easier to get the general picture. It was sold at moderate cost and back copies are more readily available outside TPM, although they tend to be very popular when available for sale, like back copies of Wisden! A few dozen copies in the period 1856-1921 are available in PDF form from the downloads section.
Postal Rates Leaflets
For rates from the 1960s onwards, the leaflets that were (and are) placed in racks at Post Offices are a key source. Free to be picked up, although a complete or nearly-complete run can be tricky to get if you didn't actually pick them up yourself. (I do have a fair number of duplicates of postal leaflets from about 1985 onwards, and would be happy to swap for ones I don't have.)
For more recent rates it has been possible to download copies of the rates leaflets in PDF format from the Royal Mail website. Since modern rates are often long lists of charges with irregular steps, being able to cut-and-paste from these files has been a big help!
Notices to Postmasters and Notices to the Public
The official announcements of new developments, although the former were effectively superseded by the Post Office Circular. Again, difficult to find outside TPM, but the details tend to have been collated into secondary sources of one kind or another.
The following listing is of books that I have found to be particularly valuable (this is, I hasten to add, a personal opinion). Not all of them cover areas currently covered on this site, but extensions are also on the to-do list! Any sources consulted for specific pages will be detailed on those pages.
British Civilian Postage Rates of the 20th Century by Michael Furfie
Simply a book you need to get if you collect 20th century GB postal history. Extremely useful; manages to pack a huge amount of information into about 60 pages, and as an A5 publication with card covers it's small and light enough to slip into a bag and take to fairs. Still available from the author at a modest price. Highly recommended.
For the Port and Carriage of Letters by David Robinson
The most helpful volume detailing pre-stamp postal rates I've yet encountered. The author takes the time to actually explain the complexities and how the various charges fit together rather than just listing the rates in sequence. Sadly it's been out-of-print for some time, although I understand a new edition may be in the works.
British Letter Mail to Overseas Destinations 1840 to UPU by Jane and Michael Moubray
The book on this topic, a high class production with extensive rates tables that actually cover the complexities of the rates in this era in the detail necessary to stand a sporting chance of interpreting a cover. The first edition was long out-of-print and expensive on the second-hand market, but a new edition was published by the RPSL in 2017 - get your copy now while you can!
London Late Fee and Too Late Mail 1840 to 1930 by John Parmenter
Deals with late fee mail in detail -- both rates and postmarks are covered comprehensively. Collectors have a tendency to attribute any odd charge they can't explain to a late fee -- this is the book that will tell you what the late fees actually were. Available in PDF form from the downloads section.