This week's announcement by Education Secretary Michael Suen Ming-yeung marks the latest round in a seemingly never-ending fight - to improve educational standards across the board while meeting the aspirations of parents who know that fluent English is the key to so many opportunities for their children.
The mother-tongue policy began as a well-meaning attempt to help all students in the public education system to achieve their full potential. But its launch triggered uproar among parents and the medium-of-instruction issue has remained a bone of contention throughout its troubled 10-year history.
The policy was introduced by the Tung Chee-hwa administration just a year after the handover after an Education Commission report found many schools that claimed to be English-medium were actually practising 'mixed-code teaching'.
The drift in the medium of instruction was the result of the laissez-faire policy towards education taken by the colonial government since the mid '70s.
The commission's 1990 report found that mixed-code teaching - using English for written work and textbooks but Chinese for teaching - was ineffective and should be abolished.
Most students left school having neither mastered English nor achieved a good standard in other subjects because lesson time was often wasted on translating texts and learning was reduced to rote memorisation of facts in English.
The new policy was also backed by a raft of research from around the world which showed that children learn more effectively in their mother tongue.
But parents wanted their children taught in English so they could gain access to university and jobs in government and international commerce - all largely needing English.
Some parents threatened to hold demonstrations or take the government to court if their children's schools were forced to switch to Chinese. Others were distressed when their children were turned away by English-medium schools in the scramble for places when the designated schools were announced.
Only 114 out of more than 400 government and aided secondary schools were allowed to continue using English for instruction from Form One to Form Three.
To do so, they had to meet three key criteria: 85 per cent of students had to be capable of learning in English, teachers had to have the ability to teach in the language and the school needed adequate support measures in place.
English-medium schools were required to teach only in English, while the remainder were forced to adopt Chinese as their formal medium of instruction in the first three years of secondary school.
Despite the policy's turbulent start, there were signs after several years that it was starting to bed down. A poll in 2002 found that just over half of adults supported mother-tongue teaching - even though 70 per cent believed that students at English-medium schools had better prospects.
The 300-odd Chinese-medium schools could choose whether to teach in English or Chinese from Form Four upwards and by 2005, half of them had adopted Chinese for nearly all subjects up to HKCEE. A small but enthusiastic minority also used it to teach A-levels.
However, five years after its implementation, the Education Commission embarked on a review to determine whether the policy should be continued. It set up a working group for a two-year consultation which generated a war of words - and statistics - over the impact of the policy on exam results.
The government cited exam results - such as a 5.6 percentage point increase in the number of Chinese-medium students gaining at least five Hong Kong Certificate of Education Examination (HKCEE) passes from 2002-2005 - as evidence that standards in Chinese-medium schools were improving across the curriculum.
Opponents pointed to a migration of candidates from the harder English syllabus B paper to the easier syllabus A. The two papers were replaced by single HKCEE in English in 2007.
Meanwhile, the Subsidised Secondary Schools Council, which represents more than 70 per cent of secondary school principals, called for schools to be given discretion over their medium of instruction after a survey showed more than 80 per cent of principals favoured a school-based approach. The Professional Teachers' Union, however, warned that such a move would create 'division and chaos'.
The working group's plan to reform the system, published in 2005, came out squarely in favour of retaining the mother-tongue policy and maintaining a strict division between Chinese-medium and English-medium schools. But it provided a complex mechanism for Chinese-medium schools to switch to English-medium - and vice versa - if they met the three criteria of the original policy, which were now quantified.
Crucially, 85 per cent of students admitted to Form One had to achieve results among the top 40 per cent of their age group across all academic subjects in tests taken in Primary Five and Primary Six. And every teacher of an academic subject at the school had to be able to show that they had reached grade C or above in the HKCEE in English (syllabus B) - or equivalent.
Teachers who did not make the grade were told they had two years to reach the benchmark, while English-medium schools that did not meet the criteria faced being forced to switch to teaching in Chinese.
All 112 English-medium schools were to be reassessed over a two-year period ending last September to decide whether they could continue in English. Chinese-medium schools could first apply in 2010 to change their medium of instruction.
The mechanism for both types of school was based on a fixed six-year cycle and involved a review of the average tests scores of the Form One intake across the whole period.
Alarm bells rang in the English-medium camp. The English Medium Schools Association protested that it was unfair to force a school in which most students were up to scratch in English to switch to Chinese because it did not quite meet the 85 per cent threshold.
Protests were mounted and more than 1,000 parents at the prestigious La Salle College and its feeder primary lobbied against the reform plan on the grounds that it would prevent the pair forming a through-train school.
Principals of Chinese-medium schools also attacked the plan, warning that the reforms would promote a negative 'labelling effect' against their schools and place them under pressure from parents to switch to English medium.
Just when everyone thought the government was sticking to its guns until the mechanism began in 2010, Mr Suen let it be known that a further review was in the pipeline.
In June, he released interim proposals for 'fine-tuning' the policy, designed to eliminate the strict divide between English-medium and Chinese-medium schools and give schools autonomy in deciding their medium of instruction.
The idea was to retain the threshold - but apply it to each class rather than to the whole school. Any class with 85 per cent of students in the top 40 per cent academically on entry to Form One could be taught in English. Other classes would have to be taught in Chinese but up to 25 per cent of class time could be set aside for 'extended learning activities conducted in English'.
The full proposals, released yesterday, pledge to increase students' exposure to English while minimising the 'labelling effect' on Chinese-medium schools and underline the flexibility for schools to introduce English-medium teaching by class, group, subject or session, according to their particular circumstances and student profile.
Mr Suen has also given schools flexibility to transform classes that are providing extended learning activities in English for 25 per cent of the time into English-medium classes in individual subjects, once students and teacher are ready.
The adoption of a 'school-based' approach shows Mr Suen has been listening to the demands from principals on both sides of the language divide and is trying to find a middle way - albeit with a notable shift back towards English.
The question now is whether he will win enough support from all parties involved - especially teachers - to make the policy work this time.