Partly funded by The HELP (Helicopter Emergency Landing Pads) Appeal, a 25m by 25m helipad will enable seriously ill patients to be brought by air ambulance for treatment at the hospital's Major Trauma Centre.
A lift shaft in the middle of the wing is being built so that patients can be lowered quickly and smoothly into the hands of medical experts.
The helipad - which is due for completion in January 2014 - is being constructed by Miller Construction and will be the second hospital helipad in London and the first south of the river.
More top news
Teaching assistant Kevin Wilson who brutally attacked his heavily pregnant ex-girlfriend killing his unborn son, has been jailed for life.
The soldier who tripped up a suspected drug dealer running from police has been revealed, as he admitted his military training kicked in.
Richmond Park and Bushy Parks have defended their policy of culling deer twice a year - after complaints from animal rights campaigners.