Using a sharp knife, remove the green tops of the rose hips and divide the hips into halves or quarters. If you prefer, you can remove some of the seeds at this stage; removing them later is also not a problem.

Add the rose hips and water to a pot and bring to the boil. Simmer for 15 minutes. Remove any foam that forms at the top; most of the seeds will follow too.

Use an immersion blender to whiz the mixture for a few moments and simmer for 2 minutes.

Pour the mixture through a sieve and rinse the pot.

Return the hot soup to the pot together with 0.5 cup of sugar and stir until the sugar has dissolved. If you prefer a thicker soup, mix 3 tbsp potato starch with a little cold water and add it to the soup and bring to the boil briefly.