‘Milk?…Milk!’ rages Nirmal Sethia, clutching the side of the table in ill-disguised apoplexy. ‘If you put in milk and sugar then you have destroyed the taste! Destroyed it!’

I apologise and say I will happily drink my Earl Grey black. The truth is, I don’t have much choice, because I am trapped in a basement near Smithfield meat market with an impassioned tea magnate.