It is week two of The Great British Bake Off, and it is crunch time as Paul and Mary set the bakers three biscuit challenges. The bakers start with a signature challenge, but who will snap first with just a few hours to make 24 identical decorated biscuits? Hidden under the gingham cloth is a technical challenge that requires perfect piping to avoid a crumbling whirl. Sue Perkins drops in for tea and history as she discovers the etiquette of dunking biscuits, from Victorian high society right back to Greek survival biscuits. The final showstopper challenge requires precision baking to build a biscuit structure that reveals a little more about each of the bakers.