Before you start with the jam, place two saucers in the freezer. You'll need these to test for when the jam is set.

Count the damsons so you know how many stones you'll have to find.

In a large wide stainless steel saucepan, simmer the damsons in the water until soft and broken down. It will take 10-15 minutes depending on how firm the damsons are.

Turn the heat off and give the damsons a vigorous stir to loosen any stones that may not have dislodged themselves. Hunt them out with a wooden or slotted spoon and remove to a bowl.

Once you've removed the stones, tip the contents of the bowl into the sieve and press out any collected juices etc back into the jam pan.

Whilst the plums are cooking, wash your jars and place in the oven to sterilise.

Pour the sugar into the jam pan. Stir until the sugar is completely dissolved.

Crank up the heat and bring the damsons to a rolling boil. Boil until setting point is reached. This usually takes between ten and fifteen minutes. Start to test after ten minutes.

Remove from the heat. If any scum has formed on the top, scoop it off with a slotted spoon and discard. Likewise remove any stones that might have been missed and have floated to the top. Let rest for five minutes, then stir.

Using a sterilised ladle and jam funnel, pour into warm sterilised jars. Cap immediately with clean sterilised lids and twist tight.

Leave to cool then label with the date and name.