Upon arrival, I did not realize I had been booked in a basement room with no windows. This is firstly, inhumane and unacceptable, and secondly, against international building code. The room was cramped, dark, and felt extremely dangerous if there was a fire. The walls and tiles (tile wallpaper, not even real tiles) were clearly very dirty and water damaged. The wifi connection was horrible. I asked the front counter staff if I could upgrade to a room with windows, which would cost me 90£. However, their machine did not take my card (which I had no prior issues with) and the staff refused to accommodate despite the claustrophobia induced panic I was in. One staff member proposed I ask another customer to pay for me and that I pay them with cash. The staff was overall rude, unwelcoming and disrespectful. I was in the area for some concerts at the O2, and I found my experience sleeping outside the arena on the concrete in the cold a nice refuge from the hell that was this room. Especially for the price, this was the worst experience I’ve ever had at a hotel.