BEIJING (Reuters) - Hong Kong’s education system was described by the Chinese Communist Party’s People’s Daily newspaper as a “disease” that must be treated, in an editorial that blamed schools for inculcating students with values that led to illegal behavior.

Published late on Sunday night as the former British colony suffered the latest protest in five months of political unrest, the newspaper returned to a well worn theme. State media has repeatedly blamed textbooks in “liberal studies”, a mandatory high school subject in Hong Kong, for influencing students, who have been at the forefront of protests.

“Whether it’s ‘liberal studies’ education materials, or some teachers in the schoolyard, they’ve treated the classroom as the sowing ground for a political perspective,” the People’s Daily said.

The materials “ignore reality, distorts truth and are full of biased content...one can well imagine the poisoning it has brought on to the youth’s minds,” the newspaper said.

The classes in liberal studies, which started in 2009, are taken by high school students and are akin to a civics course.

“One of the basic tenets of this class is to teach critical thinking,” said Tin Fong Chak, the vice president of the Hong Kong professional Teachers’ Union.

“For instance, when we talk about Occupy Central, do you think this is right or wrong? We talk about how it impacts society,” said Tin, referring to the protest movement that paralyzed parts of the Asian financial hub for 79 days in late 2014.

China has been revamping its educational materials in the mainland in recent years, revising the content of textbooks and centralizing publishing.

Last week, the Ministry of Education unveiled new guidelines to remove and punish “unqualified political teachers,” while promoting those deemed exemplary.

It followed reforms in August directed at the curriculum for a mandatory political education course that “must continue to march in step with the Party’s new ideology, to comprehensively push Xi Jinping’s New Era of Socialism with Chinese characteristics into the students’ heads and to allow the socialist core values to permeate through our national education system.”