Pour the berry and sugar mixture into a large pan and bring to the boil very slowly, stirring frequently.
Then boil fast until setting point is reached.
Remove from heat and skim off any scum that may have formed on the top.
Pour the hot jam into warm, sterilised jars and seal.
The simplest method for checking for a good set is to place a saucer in the freezer so that it is very cold. When you think the jam is ready, place a little on the saucer and leave it until it cools down before running your finger through the middle of the jam, the surface should wrinkle and the jam should not run back and fill the track your finger has made.