On December 2nd, an Amazon warehouse in the Welsh city of Swansea packed up and sent out some 450,000 items. That effort would have been impossible without a small army of temporary staff, hired from the local region as "elves" to assist with the online retailer's Christmas rush. The Guardian's Carole Cadwalladr joined their ranks last month to investigate "the employer of last resort" in the Welsh city, entering a warehouse — Amazon prefers the term "fulfilment center" — a quarter of a mile long in which underemployed staff are subjected to 10-hour days and summarily laid off without warning.