Preheat the oven to 190 C / Gas 5. Firstly slice the loaf and cut off the crusts, then butter all the slices (but throw the crusts away, or dry them to make breadcrumbs). When all slices are buttered, cover the bottom of a large baking dish with a layer of bread.
Now add a tablespoon of sugar and sprinkle some raisins on top, and keep adding more layers of bread and putting sugar and raisins on top of them.
When you have placed the final layer of bread, mix the milk with the eggs and pour this all over the pudding.
Now put the pudding in the oven at 190 C / Gas 5 for about 25 minutes.