The following document has just been published by RCSEng:

http://www.rcseng.ac.uk/rcseng/content/publications/docs/Shift_working_
for_surgeons_in_training.html

It details their stance regarding shift working in surgery. It is
well written and has many good references. In particular, it states
that ideally senior surgical trainees (registrars) should NOT be
working shifts if at all possible.

It also states that if you do have to work a night shift, this should
ideally be for 1 nights only followed by a day off work. There are
good health and safety reasons for this.

I am aware that most of the shift systems currently in place are
completely at odds with these recommendations. If you feel that your
training is being adversely affected by a shift system, this document
could provide an ideal time to sit down with HR and the bosses and try
to draw up a new working pattern.

Good luck

Richard