Find a container that’s large enough to sit in your fridge. Put the flour in the container, along with the yeast, salt and sugar, and mix really well. Pour in the water and mix until you have no floury bits. Cover with cling film, leaving a small gap for the gases to escape, and leave in a warm place for as long as it takes for the dough to double in size. As soon as it has, pop into the fridge overnight.
Have a baking tray ready, lightly greased and lined with some baking paper. This is the tray on which we will bake our free-form bread dough. Take the dough out of the fridge and lightly flour the work surface. Tip the dough out onto it.
Knock the air out and flatten the dough. Tuck in the ends, into the centre, turn the dough around, seam- side down, and pop onto the tray. Cover with clingfilm and leave to prove till an indent made in the dough stays there and only comes back up slowly.
Preheat the oven to 220°C/Fan 200°C/Gas 7. Pop a roasting dish in the base and fill with hot water. This is to create steam, which will give the loaf a chewy crust. Uncover the dough, slash the top in three places and bake for 25–30 minutes. You will know the bread is baked if, when tapped underneath, the loaf sounds hollow. Leave to cool completely on a cooling rack. Slice and enjoy with good cold butter and pinches of rock salt.