1kg sugar with pectin
Juice of half a lemon
Optionally you can add some gooseberries, up to 8oz and or some red currant jelly. Not the bought stuff but some which you have made yourself earlier in the season.
Put the strawberries in a preserving pan with the sugar and lemon juice. Heat gentlly until the sugar is dissolved.
Bring to the boil and boil steadily for about 4 minutes until setting point is reached.
You can add a knob of butter as this helps to reduce the scum.
Allow to cool and remove the scum.
Stir the jam gently and pour into sterile and warmed jars.