The theory was first published in 2005 a press released under the name of Cliff Arnall, who at the time was a tutor at the Centre for Lifelong Learning – a Further Education centre associated with Cardiff University. Later, however, the Guardian printed a statement from the university distancing itself from the psychology professor: “Cardiff University asked us to point out that Cliff Arnall… was a former part-time tutor at the university but left in February.”

Blue Monday, which falls on 18 January in 2016, is allegedly the most depressing day of the year. Understandably, tightened purse strings following the festive splurge, time passed since Christmas and failed new year resolutions is not a combination for happiness – but why is the third Monday in January apparently the worst day of the year?