The son of a friend recently had an accident at work. We believe it may have been caused at least in part by him being over-tired. I don't want to give too much detail here, but basically he works 9-5 but has to do overnight on call for a full week every 3 weeks or so. It's not unusual for him to be called out a couple of times in one night in the small hours (not every night) but his employers still expect him to be back at work 9am next day.
I believe there is law covering the amount of time you have to be away from work after working at night but can't find the info.
With respect can I ask at this time that people refrain from giving opinion, tempting as it is, unless that opinion is backed up by legal fact.