The third and final heat in this Great Sport Relief Bake Off, a charity special hosted by Mel Giedroyc. The final four personalities take on more Bake Off challenges in hope of getting the last place in the grand final.Stepping up to the hotplate to have their baking scrutinized are TV presenter Anita Rani, singer turned fashion designer Pearl Lowe, BBC weatherman Alex Deakin and TV historian and archaeologist Alex Langlands.Judged by acclaimed master baker Paul Hollywood and legendary cookery writer and baker Mary Berry, the bakers start with their signature bake - a classic crumble. Paul's prediction that it's a dish that is 'easily made, but easily messed up', turns out to be true as some attempt risky, innovative twists on this most British dish. Some, however, triumph with bold, unusual ingredients, and for one lucky Sport Relief baker they hear the rare word 'stunning' slip through Paul's lips.Fear fills the tent when the dreaded technical challenge is revealed - to bake Mary Berry's own classic coffee and walnut cake. A big ask for one baker, who has never attempted to make a cake before.Finally, the bakers are asked to create 24 perfectly finished showstopping miniature tarts. A red hot chilli threatens to blow the judge's heads off, and a blowtorch to a batch of lemon meringue tarts pulls off a professional finish and a nod of approval when it comes to judging.Who will have what it takes to impress the judges and take the last spot in the final?