Add the gin, syrup, lemon juice and vinegar to a shaker filled with ice and shake until chilled.
Strain into a tulip glass over ice, top up with the ale, and fill with more ice.
Garnish with freshly grated cinnamon, 1 cinnamon stick and a straw.
*Wild plum syrup: Add sliced plums and sugar (2:1, plums:sugar, by weight) in a small pot and cook over medium heat until the plums become very soft and the sugar is completely dissolved. Strain out the solids through a chinois, and let cool.