As a fellow brit, my understanding has always been that the tea needs to go into water as close to boiling as possible, and putting the water into a cold pot makes that much harder. Unless in a rush I tend to use the water from pre-heating the pot to also pre-heat the cup so my brew stays hotter longer.

> the tea needs to go into water as close to boiling as possible

Many teas go bad when put in too hot water, green tea comes to mind, but I'm sure there are others as well. These kinds of teas should never be in water that is anywhere near boiling.

As a British expat living in Asia, I was heavily amused to read this passage in Neal Stephenson's The Diamond Age:

There was lengthy discourse between the two men on which of them was more honored to be in the company of the other, followed by exhaustive discussion of the relative merits of the different teas offered by the proprietors, whether the leaves were best picked in early or late April, whether the brewing water should be violently boiling as the pathetic gwailos always did it, or limited to eighty degrees Celsius.

I rarely make tea, but I vaguely remember when I did long ago, that on rare occasions it was bitter and I kind of attributed that to having the water too hot. I assumed it wasn't a problem usually because I wasn't brewing it in a large teapot but after pouring into a mug during which the temperature drops substantially.