A month-long labour dispute at a Mexican factory making costumes under the Barbie label, licensed by the US toy manufacturer Mattel, has led to allegations that workers as young as 13 were employed making the costumes sold throughout the US and Europe...The manufacturer, Rubie's of New York, which denies the use of child labour at the plant, has subsidiaries in the UK, France, Germany, Portugal, Spain and Japan...Mattel says it is investigating the allegations and admits that it has identified, through an internal audit, one 15-year-old working at the factory...