Wash the fruit and put it whole and unpeeled into a saucepan. Pour on 2 pt. boiling water and simmer gently with the lid on the pan until the fruit is tender enough to be pierced easily with a fork (approx. 2 hr.). (Alternatively, the whole fruit and water can be baked in a covered casserole in a cool oven until the fruit is soft; this will take about 4–5 hr.) When the fruit is tender, cut it in half and remove pips, then cut up the fruit with a knife and fork, carefully retaining all the juice. Return the pips to the water in which the fruit was cooked, and boil for 5 min. to extract more pectin. Put the sliced fruit with the liquid (strained free from pips) and lemon juice in the preserving-pan. Reduce the heat, add the sugar and stir till dissolved. Bring to the boil and boil rapidly till setting point is reached.