Put the blood orange juice and sugar into a saucepan and warm over a gentle heat, stirring until the sugar has dissolved. Add the glucose, remove from the heat and stir again until dissolved. Pour in the Campari and lemon juice. Transfer to a metal bowl and leave to cool, then chill.

Churn in an ice-cream machine following the manufacturer’s instructions, then firm up in the freezer. Alternatively, put the bowl in the freezer for one to two hours until the edges start to freeze. Whisk into the center, then freeze again. Repeat every hour for the next two to three hours until the sorbet is smooth. Return to the freezer to firm up.

Serve in small bowls or glasses that have been chilled in the freezer for one hour beforehand. The alcohol means it will melt quickly.