It's the semi-final of the Great British Bake Off, and the four remaining bakers are all desperate to claim their place in the final. The remaining bakers know they are just three patisserie challenges away from the biggest day in their baking lives. First comes the signature, and there's no business like choux business as the bakers must set to work on producing 24 exquisite choux buns. Prue has set a complex technical for her first semi-final that leaves everyone stumped. And there's a meringue sculpture showstopper where the bakers mustn't crack under pressure. Who has the skill to reach the Bake Off Final and who will leave the tent?

'Tis the season to be jolly. And what better way to celebrate, than with the first of two Yuletide specials of Bake Off? Eight merry bakers from Bake Off past join Sandi Toksvig and Noel Fielding as they do battle in festive-themed challenges. It's down to judges Paul Hollywood and Prue Leith to decide who wins the festive Star Baker title. In this episode, Sandi, Noel, Paul and Prue return to the tent for a traditional Christmas get-together. Also invited to the celebrations are Val and Selasi, Paul Jagger and Beca Lyne-Pirkis - all of them ready to do battle in the festive fight for the Christmas Star Baker title.