These guys know. They scaled the bastard a few weeks ago, apparently without any permission. Just walked in, climed up, and took some stunning pictures. They followed the ascent with a quick peek inside.

There's major works going on everywhere, and we were dodging the workmen as much as we could. Finally, we came to the stadium in the centre of the dome. I had no idea this existed, or that it could possibly exist in the dome. It's like a tardis in there...

The trip is just one of many site visits on the UK Urban Exploration forums. There's plenty of other London stuff, including but not limited to:

Mail Rail tube line
River Westbourne: "some interesting smells and some interesting finds including: tampons, sanitary towels, condoms, etc...... even whole shits"
River Fleet.
Camden Catacombs.

Sometimes, there really is no better word than 'awesome'.