Hotel cleaners spend 10 million hours of work time annually folding toilet roll, according to a new study.

Researchers in Sweden set out to prove that the custom was a global waste of time and effort.

Rickard Ljung from the Karolinska Institutet in Sweden suggested that, if only for the sake of the cleaners, the practice should be halted.

"Is it really defendable that someone else has spent time on folding the toilet paper you are about to use?” he said. "To take away unnecessary duties from hotel room cleaners would increase their health and wellbeing and save time."

As part of the research, published in the Journal of Occupational Medicine and Toxicology, he and two colleagues attempted to measure the time it took to fold a toilet roll to a hotel standard. The average time  calculated per "folding toilet paper event" came in at just under six seconds.

Taking into account the time taken to divert to the loo roll while cleaning a bathroom, they assumed an overall time per folding event of 10 seconds. This meant that given hotel occupancy rates of 50-70 per cent, and 15 million beds in the kind of major hotel chain that likes triangular toilet paper, Dr Ljung came up with the estimate of 10 million hours wasted a year.