Antiques Roadshow is at Alexandra Palace, the birthplace of television, for this special edition of the programme to celebrate 100 years of BBC broadcasting. Ronnie Archer-Morgan is thrilled to revisit the world of children's television with Baroness Floella Benjamin, together with Humpty and Jemima from Play School, while Fiona Bruce gets to lay her hands on the original shooting script from legendary comedy series Hancock's Half Hour, brought in by actor and collector Neil Pearson.