Peel the oranges with a potato-peeler and cut the zest into very fine julienne strips (about the size of pine-needles).
Dissolve the sugar substitute in the water in a small saucepan and bring to the boil. Throw in the julienne of orange peel and allow to simmer very gently for one-and-a-half to two hours. The orange zests will almost have become caramelised in