Rinse the berries and pat dry. Combine the currants and strawberries with sugar in a saucepan. Simmer over low heat for about 5 minutes, until sugar dissolves and forms a berry juice. Add the raspberries and cook an additional 3 minutes, stirring occasionally, until the berries are soft.
Trim the crust from the bread. Cut a slice of bread so that it snugly fits the bottom of a 1 liter (approximately 4 cups) bowl. Line the sides of the bowl with the 4 or 5 slices of bread, depending on the shape of the bowl.
Pour the berry mixture into the bowl. Cover the berries with the remaining bread slices. Cover the bowl with plastic wrap and top with a small plate with a weight on top (such as a can of food). Chill overnight in the refrigerator. To serve, unmold the pudding onto a plate and garnish with fresh fruit.