Sources

References

Every figure in a checked note is traced to a source with standing: legislation and government guidance first, then accreditation and standards bodies, trade federations and established consumer bodies, with a manufacturer's own data sheet only for a product specification. Each source is fetched and read before it is cited. This page is the whole list, built from the notes themselves, last checked 17 October 2026.

We also keep a companion register of British Standards that have been withdrawn but are still quoted as current in UK building guidance, with the successor to cite instead. It is free to use.

Some cited prices were published in an earlier year and have been moved to today's money on a published index. Where that has happened the figure carries a tag saying so, and this explains exactly what that does: which index, how wrong it has been when we measured it, and the cases where we refuse to do it at all.

Who the sources are

• 780 National legislation and government
• 49 Local authorities
• 314 Accreditation and standards bodies
• 170 Trade federations
• 111 Consumer bodies and charities
• 344 Manufacturer data sheets
• 331 Other

Most cited: Ministry of Housing, Communities and Local Government (1279), The National Archives (1049), BSI (285), Planning Portal (169), Health and Safety Executive (130), Ofgem (101), Historic England (58), Property Care Association (47), The Institution of Engineering and Technology (42), Energy Saving Trust (41), Royal Horticultural Society (39), VELUX (30).

A source that no longer says what a note relies on, or a figure you can trace to a better authority: tell us and the note is corrected.