According to multiple sites, GW is in the process of reducing their product range, and thus overhead, by discontinuing their range of specialist games such as Necromunda and BFG, and also both of their ranges of collectors models for Fantasy and 40K. Items remain available until stock runs out, after which there will be no replacement production. These were very low-volume sellers and they are no longer prepared to justify keeping them.
Forge World is also ceasing production of all related products.
For more, and for links to various other sites reporting on this, see:
http://www.dakkadakka.com/dakkaforum/posts/list/524399.page;jsessionid=120C3A01FDCFC77321B54009F91CBF19
http://www.dakkadakka.com/dakkaforum/posts/list/524134.page;jsessionid=120C3A01FDCFC77321B54009F91CBF19