1. Remove any stalk ends from the lemons or limes, scrub and dry them thoroughly.
2. Using a potato peeler or sharp, narrow knife, peel off the rind in thin downward strips, being careful to leave all the white-pith behind.
3. Chop or scissor the thin peel into 1/4 in. wide strips and set them aside.
4. Cut the lemons or limes in half and squeeze out all the ]uice, saving the pips.
5. Cut away the pith with a sharp knife, leaving the pulp.
6. Chop the pith roughly and tie it in a large piece of muslin, together with the pips.
7. Cut the pulp into small chunks and put them in the pre serving pan, with the chopped peel and the muslin bag.
8. Strain the lemon or lime juice into the pan and add the water.
9. Bring the fruit mixture to the boil over low heat and simmer, uncovered for about 2 hours or until the peel is quite soft and the contents of the pan have reduced by about half.
10. Remove the muslin bag, and add the sugar, stirring continuously until it has dissolved.
11. Turn up the heat and boil the marmalade rapidly until setting point is reached, after 15 - 20 minutes.
12. Skim the marmalade at once, then leave to cool and settle tor about 30 minutes.