I love the incredible sweet juiciness and perfume of nectarines. The acidity of the grapes and the aromatic flavour of Campari make this a delicious salad. Serve it in large wine glasses.
Place the sugar, water and citrus juice in a saucepan and stir over low heat to dissolve the sugar, taking care that the sugar is dissolved before the syrup boils, then simmer for 2 minutes. Pour into a bowl to cool. When cold, add the Campari, then taste, adding more lime juice if it is too sweet. Refrigerate until really cold.