As part of the Biennial the RIBA North West team did tours of Copperas Hill, the former Royal Mail sorting office. It was a fascinating tour. The most unnerving part was the security corridors. Hanging from the ceiling are these security corridors with tiny darkened windows in. Security would walk around watching the staff below sort the mail. I can understand the need for security but it felt like something from a dystopian sci-fi novel.