“Adventurous plans to build a new huge extension – described as a cut-glass ziggurat – at the Tate Modern gallery in London will be unveiled this week to warm applause from large parts of the architectural world and some criticism from design experts. The Twentieth Century Society, which was consulted on the plans, said the stepped pyramid extension – to be shown for the first time on Tuesday – detracts from the architectural importance of the existing gallery and warns that it has ‘serious issues’ with the plan.”