The BBC has been criticised for removing a Horrible Histories episode that featured slavery, chimney sweeps and Victorian child workers.
The corporation has also edited out several sketches from various other episodes.
This includes a spoof craft show in which Madame Tussaud makes wax death masks from severed heads.
The comedy has been praised for getting children to engage with the past by featuring some of its more gruesome elements.
One sketch in the missing episode shows Roman slaves chained on a boat and told that, unlike Roman passengers, they will not be allowed to escape if the ship sinks.
Another is a compensation advert for exploited Victorian factory workers featuring disabled children.
The BBC said the changes were made seven years ago to ensure the programme met guidelines for children's programmes.
Historian Guy Walters told The Times: 'This is an insane decision. Children love horrible things.'
Horrible Histories previously came under fire for suggesting Britain had historically failed to produce anything of note, relying instead on imports