Latest report from the BBC at
http://news.bbc.co.uk/1/hi/england/london/7424980.stm :

"A Transport for London spokesman said 'just debris from engineering works'
fell on the tracks rather than a partial bridge collapse as reported
earlier.
'The contractors were jacking up the bridge. The jack collapsed and debris
from the supports for the bridge fell onto the tracks. We are investigating
the incident,' he said."


--
Richard J.
(to email me, swap 'uk' and 'yon' in address)