Seen from below the finial balls gave symmetry and elegance to the balustrade round the County Hall roof.
From above, I sometimes thought, they got in the way of a good view.
When architects were assessing the work needed on the County Hall roof they found the finial balls were not secure enough. As a result they have been removed, probably until 2012.
The roof has also been closed to the public because of Health and Safety concerns. Better safe than sorry I am afraid.