Claudia Winkleman, Ed Byrne, Martha Kearney and Olympian Helen Glover try to impress the judges in the last round. Attempting to prove that they've got what it takes to claim the title of Comic Relief star baker, they attempt signature chocolate biscuits, get to grips with a family size lemon meringue pie and try to celebrate Comic Relief's 25th anniversary with a showstopping birthday cake.