Forget BS7799 and ISO27001, the one we really need to know about is BS6008: "Tea — Preparation of liquor for use in sensory tests." This is a six page, 5000 word guide to how to make a cup of tea. Section 7.2.1 states:
Preparation without milk
Fill the pot containing the tea with freshly boiling
water1) to within 4 to 6 mm of the brim
(i.e. corresponding approximately to 285 ml in the
case of the large pot and 140 ml in the case of the
small pot described in the Annex) and put on the lid.
Allow the tea to brew for 6 min....
The document does not identify what type of tea to use, nor the colour of the pot. I'm not sure if these are considered important. Although if they are going to go to the trouble of producing the document you'd have thought that someone would also have considered other aspects such as whether to slurp or sip...
I'm all for a nice cup of tea, so I'll be printing out this standard and putting it on display next to my latest security awareness poster.... :-)