I was walking down oakhill road sw18 in east putney on my way home from work when i noticed an unusual shaped object in the distance moving toward my general direction. there were a few low altitude planes in the sky during the observation on their usual predictable flight path into heathrow. the object was high in the air, the planes and the small cloud to my left gave me an indication of size and altitude. it must have been quite large but not the size of a 747 at all, perhaps 7-12 meters wide. the sky was crisp and clear and the object was reflecting sunlight off it's surface. the surface was metallic in nature, but not heavy looking. the central top area was illuminated by itself or reflecting the most light. when i first saw it in the distance the entire craft was reflecting sunlight, brightly. when it was to my left it was the central area that was illuminated. i watched for a minute and noticed it had no wings and no port/starboard lights and moved without making a noise as it was getting closer but still quite high. i took out my iphone 4 and took some pics as it moved over to my left. i even tried to zoom in but didn't get a decent shot, only about 5 shots on the standard setting making it appear quite small in the frame, yet for me identifiable. the disc moved at an even pace quite slowly all through its trajectory. it appeared too slow for a fixed wing craft to sustain lift. it was not a helicopter, there was no noise at all, perfectly silent all the time with no flashing lights. i have seen orbs before and this was the first time i had seen a large domed disc, so i was happy to see it. the object moved out of sight over trees and rooftops to the ene.