Thanks LaFoto.
It's the effect I was going for. I originally wanted to shoot the stadium in bright, perfect sunshine, looking really clear. I got there too late, however, during sunset, so I had to bump my ISO up to 800 to get enough shutter to use with my 200mm lens.
The result was quite noisy, and there was no point pretending it was a perfect shot, so I converted to B&W, gave a little vingetting, increased the contrast (which is why the buildings have little detail), and generally enhanced the rough effect. As I wrote on my flickr: "A low light, high ISO, old-school effect take on the new Wembley. Gritty. "