You can download the two pdf's, which Konqi has posted excerpts from above, via this link,
http://www.lda.gov.uk/server/show/ConWebDoc.1120
especially parts 2a and b [seem to remember sending a link to a grateful Falkor some years ago now.]
Why did they clear the terraces? Sir Henry Buckland still had hopes of a conference centre, as counterpart to the sports centre, being built on the site of the Palace, before Birmingham was finally chosen, and all those [by then very weathered] urns, statues and fountains were just so much Victorian tat I expect. Apart from some restoration work in the 80's, the site and terraces remain no more, architecturally, than the cleared site it was in the 1930's.
Most things seem to be demolished in the hope of being replaced with something better, turnstiles and granite benches come to mind. The LDA "dig" was just the kind to establish whether the groud is safe to build on.
Despite the numerous plans over the last 73 years to redevelop the site, nothing has happened, which has left Londoners to wonder what did stand there.
Arson, still a problem in the park today, put paid to the last vestiges of the building, the wings and colonnades, and the Canadian Parliament buidling which was only plaster and wood anyway.
An interesting parallel would be the Festival of Britain buildings, erected by a Labour government, and demolished by a Conservative one, on the grounds that they hadn't been designed for permanance, and the future maintenance costs for temporary structures was unjustified.
Goodbye skylon, . . . . .or is it hello?
http://londonist.com/2009/05/skylon_mot ... _to_be.php