Yes, indeed. It's depends on the job and how long you've worked in the NHS. I did a stint in psychiatry (working I mean, not as a patient!) and as a Mental Health Officer my normal retirement age would have been 50. Those who started employment later had different conditions and their normal retirement would be later.
In many jobs you may take early retirement but, of course, the income you receive will be less. At the moment the minimum age is 50 but that is going to rise to 55 in 2010.