There are plenty of boats to board in London but how about stepping on board a genuine Cold War submarine? If you take a day trip to Chatham Dockyard then you can see what it’s like inside HMS Ocelot. To say that it’s cramped would be a massive understatement, it’s like you’re walking through corridors of pipes and dials and the doors (if you can even call them doors!) are the same size as a dinner plate. You almost have to be an acrobat to squeeze yourself through them. That line of buildings you can see at the back of the photo is where they filmed a lot of scenes for Call The Midwife – whenever you see a nun cycling along the docks that’s invariably where they are.