Heat the oil in a saucepan, add the onion and fry for 5 minutes until softened but not browned. Stir in the red pepper, celery and tomatoes and fry for 5 minutes, stirring occasionally.
Pour in the stock, add the sugar, Worcestershire sauce, tomato purée and a little salt and pepper and bring to the boil. Cover and simmer for 15 minutes.
Allow the soup to cool slightly, then purée in batches in a blender or food processor until smooth. Sieve if liked then pour back into the saucepan. Add the vodka and Tabasco to taste, and adjust the seasoning if needed. Chill well.
Ladle the soup into small bowls or glasses, add tiny celery sticks, drizzle with a little extra olive oil and sprinkle with a little extra pepper.