Preheat the oven to 180°C/350°F/Gas 4. Line a 2lb (or two 1lb) loaf tins with grease proof paper and set aside.
In a bowl mix together the flour, baking powser, barcarbonate of soda and salt.
In a separate bowl mix the chocolate chips with a 1 tbsp of flour of the flour mixture. This will help to stop the chocolate chips dropping to the bottom of the bread.
Beat together the sugar and butter with an electric whisk.
Beat in the eggs and then add the mashed bananas and vanilla extract and mix together.
Fold in the flour to make a smooth batter, then finally add the chocolate chips.
Spoon into the tin and bake in the oven for 45-60mins (depending on whether you are using a 1lb 45-50mins or 2lb tin 50-60mins). Insert a skewer into the centre and if it comes out clean it's baked through.
Allow to cool slightly then remove to a wire rack to cool completly.