What's going on here?

Out in the town centre with my two children today, we came out of the shopping mall to be greeted by this. This office block has been empty for years, and there have been long-rumbling plans to pull it down and put a supermarket in its place.

Well, it looks like they finally got round to doing something about it. My son was fascinated by the diggers, while my daughter was fascinated by the building itself.