My second corporate shoot of the day on Thursday took me to almost the very top of One Canada Square, which used to be the UK's tallest building until The Shard overtook it.  I was there to shoot portraits but while I waited in reception I was mesmerised by this view over the O2, Thames Barrier, London City Airport and the Dartford Crossing 15 miles away in the haze.  How anyone up there with a desk near a window gets any work done I have no idea.