@GreenTeaLikesMe
I don't think anyone is disputing that London needs housing, although, to be honest, a lot of new builds in the area seem sit mostly empty. I'm not sure why you're choosing to argue over this, but if you're not local, I'd suggest you go walk around the site.
You'd have to find a developer who believed it would be in their interest to build there. And considering the inevitable community opposition - the consultations would very likely go on for years, the need to deal with the site contamination, the size of the footprint and the access issues, I think you'd have a hard time. If the fire engines could barely get in, how will the construction equipment? And since the footprint is so small, the only thing that would make sense is another tower, and I struggle to see that going down well locally.