It's a bathroom-themed semi-final as the potters make Turkish bath-style sinks and tiles and attempt Moorcroft tube lining. Who will be feeling calm, and will there be water works?

Siobhán McSweeney hosts a special Christmas episode, joined by celebrity contestants Hugh Dennis, Sophie Duker, Alice Levine and Joe Swash. Judges Keith Brymer Jones and Rich Miller set two festive challenges - hand-building a Christmas birdhouse and a surprising second task where speed is of the essence, as the celebrities take to the wheel to see who can throw the most festive nibbles bowls.