I can find bugger all history on this place which is really supirsing given how big it is and its age but all I can find is (Taken straight from Wikipedia)
"During the year that he was Mayor of Derby, Sir Alfred Seale Haslam managed to replace the old William Strutt Infirmary with the Derbyshire Royal Infirmary. In 1890 there had been an outbreak of disease at the old infirmary and Sir William Evans, President of the Infirmary arranged a three day inspection which condemned the old building. When Queen Victoria came to open the new hospital on 21 May 1891 she knighted Haslam for his services and gave permission for the term "Royal" to be used."
Unfortunately our visit was cut short by the security guard, who I can only describe as Dog the Bounty Hunter's brother from Derby, spotting us on the cameras (the hospital is still half live) and coming to find us. After a bit of cat and mouse with him he caught us, walked us to the front door and had the police called who came and took our names and told us to be on our way. I would have loved to see the rest of this place because, as the guard was walking us to the main entrance, I found the main corridor is huge - it went on for ages with doors on either side leading to different departments. But the police are apparently (I don't know how true this is) taking names and if you're caught there again it won't just be a slap on the wrists and being told to leave.