Wash fruit and vegetables thoroughly and allow to drain. Score the skin of the tomatoes in a cross shape, briefly pour boiling water over them and peel. Remove the stem end and cut into pieces. Core sour cherries. Chop the strawberries a little. Chop the chilli peppers with the seeds.
Puree the fruit and vegetables together. Add the preserving sugar and cook for 5-7 minutes until the gelation test works.
Fill immediately into clean screw-top jars and close tightly.