1. Put the tea, ginger and spices into a saucepan, pour on 1 litre boiling water and bring to the boil. Lower the heat and simmer until you can smell the spices, about 10 minutes.
2. Add the sugar and milk, turn up the heat and bring to the boil. Allow 10 minutes, stirring occasionally. (A skin will form, but this is strained off at the end.) Taste to see if the chai is to your liking; boil a little more if you wish for a stronger flavour. Patience will be rewarded!
3. Strain, discard the solids, and serve immediately.