Place a colander over your jam pan and cut your fruit in half then squeeze all the pips and pith from the lemons and oranges into the colander. The juice will drip into the pan.

Wrap the pips and pith in the muslin and tie it up so nothing can escape,

Finely slice all the orange and lemon peel and place it in the pan with 3 litres of water and the muslin.

Simmer fruit with lid off for about 2 hours. Fruit skin should be extremely soft and melt when you squeeze it between your fingers. The amount of water in the pan should have roughly halved.

Remove muslin bag and leave to cool.

Once it cool enough to handle squeeze all the jelly like substance muslin produces into the jam pan and stir into the fruit.

Add 3 kilos of golden granulated sugar and stir until melted.

Turn the heat up and rapidly boil the jam for about 15 minutes or until it reaches setting point. Turn off the jam and test for setting point.

Keep some saucers in the freezer for this. Dab a splodge of marmalade on the saucer and put it back in the freezer to cool for a couple of minutes. Then drag your finger through the jam. A skin should have formed. If its not ready reheat for a couple more minutes.

Once setting point is reached turn cooker off and leave jam to stand for 15 minutes or all the fruit will rise to the top. Stir gently. I use a measuring jug to pour the hot marmalade into sterilised jars. You can put wax discs on top of the marmalade before you put the screw tops on if you want to. (I don't bother!)

If for some reason jam doesn't set simply reboil and retest for setting