The situation is a little funny on this one It closed in 2001/2002 and part of it has just been left to rot but other parts still take deliveries and ship things out which is a little strange. It's apparently been given the go ahead for demolition this november.
This website here has a really in depth history of the site from its conception to the current date. So I shall just point you towards them.
This is quite possibly my new favourite place I've been. Setting of at 3 in the morning from Leeds for the long drive down to Lincolnshire and getting up early was definitely worth it. Visited with Clough and Hidden Shadow aka Hidden sandwich as he seemed to have an endless supply of sandwiches throughout the day.