Alice and Beatrice are charged with robbing Charlie one evening in a badly-lit pedestrian subway. The case for the prosecution is that Alice approached Charlie and offered him sexual services, and that, while Charlie was negotiating with her, Beatrice hit him from behind, causing him to fall to the ground. The two women then searched him and stole a wallet, a watch and a gold chain. Charlie picked out Alice from police photographs, after which she was arrested. When interviewed by the police in the presence of the duty solicitor she said, 'It was all Beatrice's idea. I didn't want to have anything to do with it, but Beatrice threatened me and I was frightened.' The police arrested Beatrice. She asked to see her own solicitor, and on his advice refused to answer any police questions. The defendants are separately represented; each intends to plead not guilty. Alice will rely on the defence of duress. Discuss the evidential matters arising.