Apple has admitted that child labor was used at the factories that build its computers, iPods and mobile phones.

By Malcolm Moore in Shanghai

Apple has been repeatedly criticized for using factories that abuse workers and where conditions are poor.

At least eleven 15-year-old children were discovered to be working last year in three factories which supply Apple.

The company did not name the offending factories, or say where they were based, but the majority of its goods are assembled in China.

Apple also has factories working for it in Taiwan, Singapore, the Philippines, Malaysia, Thailand, the Czech Republic and the United States.

Apple said the child workers are now no longer being used, or are no longer underage. “In each of the three facilities, we required a review of all employment records for the year as well as a complete analysis of the hiring process to clarify how underage people had been able to gain employment,” Apple said, in an annual report on its suppliers.

Apple has been repeatedly criticized for using factories that abuse workers and where conditions are poor. Last week, it emerged that 62 workers at a factory that manufactures products for Apple and Nokia had been poisoned by n-hexane, a toxic chemical that can cause muscular degeneration and blur eyesight. Apple has not commented on the problems at the plant, which is run by Wintek, in the Chinese city of Suzhou.