It's simply so you don't put too much milk in. Whether rationing or not, without eyeballing if the white liquid you put in the white cup is enough, or you need 1ml more.
If you put the tea in first and milk last, you see the colour change as you carefully titrate the milk in and disaster can be averted :)
> The milk-first school can bring forward some fairly strong arguments, but I maintain that my own argument is unanswerable. This is that, by putting the tea in first and stirring as one pours, one can exactly regulate the amount of milk whereas one is liable to put in too much milk if one does it the other way round.
I wonder if wasting milk was a greater concern at the time, when the country had recently come out of rationing.
Personally, I am also milk-first. There's less risk of the milk denaturing as it heats up more slowly. This is especially true for alternative milks such as oat or soy (which Orwell no doubt would have despised).
