A BBC investigation into employment practices at online retailer Amazon has revealed that staff working for the company face an increased risk of mental illness compared to other workers.
The investigation involved secret filming of a typical night shift by an undercover worker planted into the Amazon warehouse by the BBC.
The footage was then shown to Professor Michael Marmot, an expert in work-based stress, who concluded that the sorts of conditions that Amazon employees were expected to work under would result in higher rates of 'mental and physical illness'.
The BBC's Adam Littler, 23, took a job at Amazon's Swansea warehouse as the company gears up for the Christmas rush by employing an extra 15,000 staff. He recorded the secret footage for the BBC's Panorama programme.
During his nightshift, Littler was given an electronic device which notified him of the items he needed to 'pick' to fulfill orders placed online with Amazon.
The electronic device sets the employee a target number of seconds to find the item and notifies them when they fail to progress to the next item on the list in the allocated time by emitting a loud bleep.
Professor Marmot said the demands of the job at Amazon involved 'all the bad stuff at once'.
"There are always going to be menial jobs, but we can make them better or worse. And it seems to me the demands of efficiency at the cost of individual's health and wellbeing - it's got to be balanced," said Professor Marmot in response to the footage shown to him by Panorama.
In response Amazon said that its workplace practices were within the law and that they were constantly engaging with their workforce to ensure the company improved.
"Together we're working hard to make sure we're better tomorrow than we are today," they said in a statement.
However, employment law experts have told the BBC that the ten-and-a-half hour night shifts could be illegal, as the law restricts the amount of heavy physical work to eight hours in any one 24-hour period.