It’s just not true that we all feel unhappy on Mondays, according to new research from the Institute of Work Psychology at Sheffield University. Dr Peter Totterdell, the author, has come up with many surprising results – not least that on days when everyone in the office seems to be in a bad mood, it could be just a regular, weekly, communal phenomenon.

Dr Totterdell makes several points that HR and other managers might do well to take on board. He has found, for instance, that Thursdays are the moodiest days of the week, and that people’s moods are most positive around noon.

Crucially for health and safety, there is evidence that accidents are most likely to occur between two and three hours into any shift. Within the normal day, however, vigilance is at its peak in the early evening.

From studying shift-working nurses, the researchers found that they did not recover in terms of either mood or performance on their first day off, but had done so by the next day. It’s therefore vital for both performance and general contentment at work for people to have two consecutive days off rather than single days.

Trainers and learners need to bear in mind that performance and memory skills peak at different times. Immediate memory is keenest in the late morning, long-term memory in late afternoon; and trying to carry out difficult memory tasks when we have passed our peak memory period can make us irritable and grumpy. But people vary widely between "larks" and "owls". Larks function best early in the day, owls in the early evening; and the mood rhythms of "morning types" peak 2 to 3 hours earlier in the day than those of the owls.