Heat the oven to 200C/180C fan/gas 6 and line a 900g loaf tin with baking parchment. Put a flat baking sheet in the oven to get really hot.

Mix the flour, bicarb, salt and sugar in a large bowl until evenly distributed. Make a well in the centre and tip in the yogurt. Bring together to make a slightly sticky dough.

Lightly dust the dough with extra flour and form into a fat log, around the same size as the tin. Put in the tin. Dip a wooden spoon in flour and make a line along the centre. Top with a small handful of oats or seeds, if you like.

Bake on the hot baking sheet for 40-45 mins or until golden brown. Leave to cool in the tin then turn out onto a wire rack to cool completely before cutting into slices.