A very simple vision really. I was walking through the underground maze that is London Bridge tube station with friends, we were making our way from one of the platforms up to street level. In front of me was a crossing between a walkway and the tunnel I was pacing through, from the right-hand entrance of the walkway, a middle aged woman appeared, she continued to walk through the crossing and into the left-hand entrance of the walkway. She was dressed in what can only be described as expensive clothing from around 1905-1915. Living in London, you see some weird and wonderful people so I thought nothing of her appearance apart from the way she seemed to walk so smoothly across the floor. I couldn't take my eyes off her. As I finally approached where the walkway and my tunnel met, the right entrance, from where she appeared, led to an escalator... the left entrance, which I saw her pass through, was closed off, a large and locked metal gate blocked the left entrance that I know I saw this lady walk through. There is some kind of generator or heater behind the gate.It was very spooky, no-one else saw her, just me.