There is no shortage of love amongst authors for the power of a good cup of tea. Indeed, everyone from Samuel Johnson to Jane Austen, Anton Chekhov to Oscar Wilde, Douglas Adams to George Orwell has commented on their love of the brewing of leaves.
Leave it to the British, though, for taking it seriously enough to write formal technical standards for brewing tea, to be able to do proper taste testing. First published through the BSI in 1980 as BS 6008:1980, it was later published by the ISO body as ISO 3103:1980. The December 2019 update (ISO 3103:2019) remains the current version as of April 2026.
The paper suggests temperatures, procedures and even schematics for both brewing and consuming vessels, and it is heavily implied that the preferred methodology adds milk to the pot before the tea, but does note that adding milk afterwards can be acceptable and offers suggested criteria for doing so.