Dr Lisa Wilde, Director of Research at Breast Cancer Campaign, comments on a study looking at occupational risks that claims more than 500 women die every year in Britain of breast cancer brought on by working nights.

She said: “Night shift working and breast cancer risk is a hugely complex area and two of the biggest risk factors, diet and physical activity, haven’t been considered in many of the studies to date. So, whilst this analysis contributes to the debate, further research is needed to fully understand the link between night shift working, lifestyle factors and breast cancer.

“The Health and Safety Executive (HSE) has commissioned a major study into the influence of night shift work on cancer, which will be completed in December 2015.”