One of the neat things about it, of course, is that with the big dig next to the visitor centre, there are three floors that will be underground there. Also, in the middle of the West Block, what was the courtyard has been all dug out, so there will be three floors below the level of the new chamber, where there was just bedrock. It was just a slab before. They have created a lot of additional space that will be available in that building.
On May 17th, 2016. See this statement in context.