If necessary, wash the raspberries or strawberries thoroughly, and remove the stalks.

To make raspberry jam, put the fruit into a heavy, stainless-steel saucepan. Strain the lemon juice, add it to the pan and cover with a tightly fitting lid.

Heat gently for 5-10 minutes, until the fruit softens and the juices appear. Add the sugar to the pan and stir over a gentle heat until every granule has dissolved.

Bring to the boil and boil rapidly for 5 minutes and no longer. Meanwhile, put 2 tablespoons of cold water into a small bowl and sprinkle 5 teaspoons of gelatine over the surface. Leave to stand until the gelatine swells.

Remove the jam from the heat. Add the gelatine and stir gently until it has completely dissolved. Pour the jam into 3 clean, warm jam jars and place a waxed paper disc on top of each jar, wax side down. Allow the jam to cool, then cover with lids or with clear, Cellophane covers. If you prefer, strain the jam through a nylon sieve to remove the pips.

The jam will last much longer if it is stored in a refrigerator.

To make the strawberry jam, put the strawberries into a heavy-based, stainless-steel saucepan, add the strained lemon juice and crush with a stainless-steel vegetable masher. Add the sugar, stir well, cover and leave to stand for 1 hour.

Then proceed as for the raspberry jam, using 6 teaspoons of gelatine. Allow the jam to stand for 10 minutes before potting.