I adore Eau de Nil, and duck egg blue. They are absolutely not the same, but nor would I describe that Fortnums colour as either. True Eau de Nil is a gloriously deep sludgy green. Duck egg is bluer, but again can range through pale translucent blue (that I’d say should be more rightly called robin’s egg blue) to a deep turquoise. Fortnum’s is somewhere in between, if we’re talking Eau de Nil or duck egg, then it’s neither fish nor fowl nor good red herring! If I had to pick, I’d put the Fortnum’s colour closer to duck egg. And Jack Monroe is a show off Fanny.