18 December 2014 Last updated at 13:27 ET
Poor treatment of workers in Chinese factories which make Apple products has been discovered by an undercover BBC Panorama investigation.
Filming on an iPhone 6 production line showed Apple's promises to protect workers were routinely broken.
It found standards on workers' hours, ID cards, dormitories, work meetings and juvenile workers were being breached at the Pegatron factories.
Apple said it strongly disagreed with the programme's conclusions.
Exhausted workers were filmed falling asleep on their 12-hour shifts at the Pegatron factories on the outskirts of Shanghai.
One undercover reporter, working in a factory making parts for Apple computers, had to work 18 days in a row despite repeated requests for a day off.
Another reporter, whose longest shift was 16 hours, said: "Every time I got back to the dormitories, I wouldn't want to move.
"Even if I was hungry I wouldn't want to get up to eat. I just wanted to lie down and rest. I was unable to sleep at night because of the stress."
Apple declined to be interviewed for the programme, but said in a statement: "We are aware of no other company doing as much as Apple to ensure fair and safe working conditions.
"We work with suppliers to address shortfalls, and we see continuous and significant improvement, but we know our work is never done."
Apple said it was a very common practice for workers to nap during breaks, but it would investigate any evidence they were falling asleep while working.
It said it monitored the working hours of more than a million workers and that staff at Pegatron were averaging 55 hours a week.
The poor conditions in Chinese factories were highlighted in 2010 when 14 workers killed themselves at Apple's biggest supplier, Foxconn.