Addenbrooke's Hospital

A spectral nurse appears when morphine is being administered to patients. It is thought that she is remorseful for giving too high a dose of the drug when she was alive. There are also stories of lights, televisions and taps turning on by themselves, plugs being pulled out, a glass of water being given to a patient by something invisible, paper cups piled upright, call buzzers sounding from empty rooms - and a nurse, perhaps different from the one above, being seen.
Ruth Roper Wylde provides many more stories about this establishment. It is said that the ghost of a former surgeon walked into an operating theatre; a nurse passing a door to a stairwell on the 8th floor heard the sound of a baby crying but when she went to open the door to find the source of the sound, the crying stopped (her colleague heard nothing); a tale talks of a child found wandering around the wards at night but after checking her wristband and contacting the relevant ward the employee was told she had died hours before; and footsteps that walked the length of a ward but no-one was seen. There have been a few incidents in the basement tunnels, too. A figure was seen but when it was followed its route ended in a blank wall and there was no way out; on another occasion, someone heard "Get out!" shouted right in their ear. On the old Adenbrookes site, a nurse was tasked with counting the beds and on the 3rd floor she saw another nurse at a desk wearing a old fashioned uniform with a head covering. The first nurse apologised for disturbing her colleague, who waved the new arrival on. On the way back, the same nurse was still at the desk and looked up and smiled. When the other nurse returned to her colleagues she was told that the figure behind the desk was a ghost and was normally stern. Finally, there seems to be something of a guardian in the hospital; nurses who go to administer morphine hear a voice saying "Be careful!" (a hospital legend says that this a nurse who once administered a lethal dose, perhaps the one mentioned above?) and an "entity" places a hand on the shoulders of staff when they go to the drugs cupboard and this is taken as a warning to be careful with the medicines.

Update 5/8/20: Researcher Tony Percy informs me, "Ward G4 (Geriatrics) seen circa 2000. Reported to adjust dose, or in general promptly responding to the bedside 'bell', by (some) patients -- rather than merely being seen on ward. Seen by both patients and nursing staff. At the time assumed to be a member of staff, rather than a ghost, by witnesses."