Tip the orange peel, rosemary, sugar and 100ml water into a small saucepan and bring to a simmer. Ensuring the rosemary sprigs are submerged, cook over a low heat until the mixture has thickened slightly, about 6-8 mins. Turn off the heat. Leave to infuse for 1 hr.

Put the teabags in a large heatproof jug and pour over 1 litre boiling water from the kettle. Steep for 4 mins, then discard the teabags. Leave to cool completely.

Stir the orange juice along with the prepared syrup into the cooled tea. Serve in highball glasses over ice. Add rosemary sprigs to garnish, if you like.