1. Line a 900g loaf tin with cling film, making sure it overlaps the sides of the tin so that you can fold it over the dessert.
2. Place a layer of vanilla ice cream onto the base of the tin, and on top of that place a few thin slices of sponge cake.
3. Cover with a row of strawberries, next to that a row of blueberries, and next to that a row of raspberries.
4. Cover the berries with vanilla ice cream, and continue layering as before till the loaf tin is full.
5. Press down firmly to make sure you seal all the holes.
6. Fold the cling film over the top.
7. Place the tin in the freezer and freeze till really hard.
8. Remove the terrine from the freezer 15 minutes before you want to serve it.
9. Dip quickly in warm water, and unmould it onto a platter.
10. On a platter topped with the berries, and a good shake of icing sugar.
Tip:For easier slicing, dip your knife in hot water.