Facebook has apologised after a Channel 4 investigation found staff at the company were told not to remove extreme content even when it violated the company's guidelines.
Inside Facebook: Secrets of the Social Network was broadcast last night.
A reporter went undercover at training sessions at Cpl Resources, Facebook's biggest centre for UK content moderation.
The reporter also spent time at their office in Dublin.
Speaking to Channel 4 News, Facebook Vice President of Global Policy, Richard Allan, said the company had failed in certain areas.
"We're one of the most heavily scrutinised companies in the world and that's right, it's right that we are held to high standards," said Mr Allan.
"We also hold ourselves to high standards.
"You've identified some areas where we've failed and I'm here today to apologise for those failings and make it clear that we do recognise that they were weaknesses, that we should not be in this position."