YouTube has blocked some British history teachers from its service for uploading archive material related to Adolf Hitler, saying they are breaching new guidelines banning the promotion of hate speech.

The video-sharing website announced on Wednesday that it would remove material glorifying the Nazis from its platform in an attempt to stop people being radicalised. In the process however, it also deleted videos uploaded to help educate future generations about the risks of fascism.

Scott Allsop, who owns the longrunning MrAllsopHistory revision website and teaches at an international school in Romania, had his channel featuring hundreds of historical clips on topics ranging from the Norman conquest to the cold war deleted for breaching the rules that ban hate speech.

“It’s absolutely vital that YouTube work to undo the damage caused by their indiscriminate implementation as soon as possible,” said Allsop. “Access to important material is being denied wholesale as many other channels are left branded as promoting hate when they do nothing of the sort.”

While previous generations of history students relied on teachers playing old documentaries recorded on VHS tapes on a classroom television, they now use YouTube to show raw footage of the Nazis and famous speeches by Hitler.

The Google-owned service sent an automated email to Allsop saying his clips channel had been removed for uploading “content that promotes hatred or violence against members of a protected group”. Much of it consisted of clips from old BBC documentaries, which are no longer easily available, in addition to cine film of Hitler’s speech the night he was appointed chancellor and a short compilation of Joseph Goebbels talking about propaganda.

Richard Jones-Nerzic, another British teacher affected by the crackdown, suggested YouTube’s policy did not take into account the extent to which the history syllabus focused on the second world war.

“Modern world study and Hitler in particular have dominated the history curriculum in the UK over the last 25 years,” he said, explaining that he had been censured for uploading clips to his channel from old documentaries about the rise of nazism.

Some of his clips now carry warnings that users may find the material offensive, while others have been removed completely. He said he was appealing against YouTube’s deletion of archive Nazi footage taken from mainstream media outlets, arguing that this was in itself a “form of negationism or even Holocaust denial”.

Allsop had his account reinstated on Thursday after an appeal but said he had been contacted by many other history teachers whose accounts have also been affected by the ban on hate speech. Users who do not swiftly appeal against YouTube’s decisions could find their material removed for good.

Both men said they had sympathy with what the site was trying to achieve and acknowledged that sometimes the archive fascist material they uploaded to YouTube was viewed by the modern-day far right.

“I have for a long time been unhappy with how my films have often been hijacked by neo-fascists through the comments section, but YouTube’s actions are far too indiscriminate,” said Jones-Nerzic.

Allsop suggested the site needed to take educational context into account rather than rely on automated processes: “I fully support YouTube’s increased efforts to curb hate speech, but also feel that silencing the very people who seek to teach about its dangers could be counter-productive to YouTube’s intended goal.”

A YouTube spokesperson said the company used a combination of technology and people to enforce the guidelines, and encouraged individuals to provide context to clips uploaded for educational purposes rather than simply uploading raw material. They said Allsop and Jones-Nerzic’s material had been reinstated after an appeal.