Water-based Harry Potter fountain pen ink from Montegrappa, in a selection of colours worthy of any wizard or witch worth their weight in gold dragon eggs.

Choose from Gryffindor Red, Slytherin Green, Ravenclaw Blue, Hufflepuff Yellow, Knight Bus Purple and Thestral Black - or perhaps this should be invisible ink?

Square profile bottle containing 50ml of ink. Gold-coloured cap inscribed with the Hogwarts School crest.