1) In a small saucepan, combine the milk, butter, and the sugar. Place over medium-high heat and cook, stirring, until the butter has melted. Remove from the heat and cool to about 42C.
2) Sprinkle the yeast over the surface of the milk. Set aside until foamy, about 10 minutes.
3) In a large bowl, whisk together the flour and salt and set aside.
4) Pour the milk and yeast mixture into the bowl of flour and mix until a soft, ragged mixture is formed.
5) Transfer the flour mixture to a well-floured work surface and knead until a soft elastic dough is formed, about 10 minutes.
6) Transfer the dough to a lightly oiled bowl, cover with a kitchen towel, and place in a warm spot (airing cupboard is ideal), until puffed and doubled in size, about 2 hours.
7) Transfer the dough to the work surface and, using your hands, gently flatten into a 25cm-long oval shape. Fold the dough into thirds lengthwise, overlapping the sides in the centre. Press down on the overlapping side to seal and make a seam.
8) Place seam side-down in a buttered 20cm by 13cm loaf tin, cover with a kitchen towel, and return to the warm spot until the dough has just risen about 3cm over the top of the pan, about 2 to 2 1/2 hours.
9) Place a rack in the centre of the oven and preheat to 200C/Gas Mark 6. Brush the top of the dough lightly with warm water and, using a sharp knife, make 0.5cm-deep slit down the centre. Bake until golden brown, about 30 minutes.
10) Remove the loaf from the pan and place in the centre of the rack. Continue baking until the loaf sounds hollow when tapped lightly with your knuckles, on the bottom and top, or an instant read thermometer inserted in the centre registers about 85C, about 15 minutes.
11) Transfer the bread loaf to a cooling rack and cool completely before slicing.