Facebook moderators are being told not to remove Holocaust denial or revisionism even in countries where that is illegal, according to leaked internal documents.

The guidance notes, published in The Guardian, show that the company does not remove offensive content in ten of the 14 countries where Holocaust denial is illegal, and that it only removes it in the others because of the threat of legal action.

By way of an example, one document says a picture of a concentration camp with the caption “Never again believe the lies” would be allowed if posted anywhere other than in Israel, France, Germany or Austria.

The Facebook documents, which include training manuals, reveals that the social media site will use “geo-blocking” only “when a country has taken sufficient steps to demonstrate that the local legislation permits censorship in that specific case”.

Citing a defence of free speech, it says Facebook “does not welcome local law that stands as an obstacle to an open and connected world” and will only consider blocking or hiding Holocaust denial comments and images if “we face the risk of getting blocked in a country or a legal risk”.

It continues: “Some 14 countries have legislation on their books prohibiting the expression of claims that the volume of death and severity of the Holocaust is overestimated. Less than half the countries with these laws actually pursue it. We block on report only in those countries that actively pursue the issue with us.”

Monika Bickert, head of global policy management at Facebook, said: “Whether reported by government entities or individual users, we remove content that violates our community standards.”