To make 6 or so jars of marmalade use about 6 seville oranges.
Quarter the fruit, remove pips and reserve them.
Slice the fruit, I like big rough cut pieces of peel in my marmalade but this is a matter of preference and you may like a fine cut finish.
Weigh the sliced fruit, to every 500g add half a litre of water. Mix it well and leave to soak for 24 hours in a covered bowl, in a cool place.
Take a large saucepan or better still a preserving pan, rub with lemon, this preserves the colour of the oranges.
Tie the pips in a piece of muslin and add to the pan of fruit, bring to the boil and then simmer until the fruit is tender and can be easily squashed between your fingers, this make take up to 3 hours.
Add 500g of sugar for every 500g of fruit, stir well and bring back to a boil, boil rapidly until the marmalade begins to look transparent. Do a wrinkle test on a saucer. Turn off heat and pot into clean, sterilised jars.
Place a wax paper disc on top of each one and then seal with a lid.