The management of Heung To Middle School in Hong Kong has been verbally attacked by members of the opposition camp in the city for refusing to renew the employment contract of a teacher who in the mid-term music exam allowed students to sing a song used by the separatists as their battle cry.

The radicals in the camp even went so far as to incite some students to form a human protest chain outside the school.

This is yet another example of the poison in Hong Kong's education sector, and highlights the urgent need to overhaul the city's education system to get rid of the separatists and those who still embrace a colonial mentality 23 years after Hong Kong's return to the motherland.

Schools have the right and responsibility not to renew the employment contracts of teachers who do not embrace their educational principles and objectives.

The political zealots from the opposition camp faulted the management of the Heung To Middle School for "ditching political neutrality", which is in fact a false proposition meant to confuse the public. Instilling patriotism is an obligation rather than an option for schools.

Educators in the special administrative region have had the duty to raise the national awareness of the younger generation since the day China resumed sovereign rule over Hong Kong. In this case, Heung To Middle School did the right thing.

All countries in the world attach great importance to national history and culture in their basic education. But even 23 years since Hong Kong's return to the motherland, efforts to cleanse its education system of "colonial remnants" remain far from adequate.

Worse, the opposition camp has falsified history, glorified foreign aggression and solidified the colonial mindset in the Hong Kong education system.

They spare no efforts in corrupting young people's minds, vilifying the national identity and demonizing patriotic devotion. The ultimate goal of their brainwashing is to train generations of blind followers to serve their separatist political agenda.

Hong Kong must build up an education system that nurtures generations of patriotic citizens. Those youths who aspire to be public officials in the SAR must respect their national identity without reservation, embrace wholeheartedly China's sovereign rule over Hong Kong, and never do anything to jeopardize the stability and prosperity of the SAR and the nation.

Exorcising schools of teaching staff with a slavish colonial mentality and kicking disseminators of separatist ideas out of schools should be the first step in realizing an education system in the SAR that is of the times and fit for purpose.