The streets surrounding Shijia primary school in Beijing were mobbed by a crowd of parents so dense that cars were obliged to beat a retreat.

At 3.45pm on Friday, 11-year-old Zou Tingting, five minutes late, bounded through the school's west gate and into her waiting mother's arms. Tingting's classes were over, but her day was just beginning – she had an hour of homework, plus lessons in ping pong, swimming, art, calligraphy and piano.

Tingting's mother, Huang Chunhua, said that, like many Chinese mothers, she once considered Tingting's academic performance her top priority; now she realises the importance of a well-rounded education. "I've seen British curricular materials, and I'm actually kind of jealous," she said. "British teachers guide students to discover things on their own – they don't just feed them the answers, like in China."

In recent weeks British parents and educators have been in a panic about the discrepancy between the Chinese education system and the UK's. In December the Organisation for Economic Co-operation and Development (OECD) released the 2012 results for its triennial Programme for International Student Assessment (Pisa) test – a reading, maths and science examination administered to half a million 15-year-olds in 65 countries. Shanghai students topped the rankings; the UK ranked 26th.

Next week education minister Elizabeth Truss will lead a "fact-finding mission" to Shanghai to learn the secrets of China's success. She plans to adjust the UK's education policy accordingly.

Yet Chinese parents and educators see their own system as corrupt, dehumanising, pressurised and unfair. In fact, many are looking to the west for answers. Huang said that some parents bribe Shijia primary school to admit their children (though she declined to say whether she had done so herself).

Tingting attends an expensive cramming school at weekends, leaving her tired. She will probably have to abandon extracurricular activities in high school to devote more time to the college admission exam, called the gaokao. Many parents consider the gruelling nine-hour test a sorting mechanism that will determine the trajectory of their children's lives.

Chinese experts are also less impressed than Truss by the Pisa scores. "Even though Shanghai students scored well on the test, this doesn't mean that Shanghai's education system doesn't have any problems," said Lao Kaisheng, a professor in the education department of Beijing Normal University. "In fact, it's the opposite."

As long as China's education system remains vast but resource-constrained, Lao added, its schools will default to testing as a reliable indicator of competence. "The education system here puts a heavy emphasis on rote memorisation, which is great for students' test-taking ability but not for their problem-solving and leadership abilities or their interpersonal skills," he said. "Chinese schools just ignore these things."

According to an analysis of the rankings, the children of Shanghai's cleaners and caterers are three years more advanced than UK lawyers' and doctors' children in maths. Yet the figures are an unreliable measure of equality. Although Shanghai's 23 million people make up less than 2% of China's population, its per capita GDP is more than double the national average; its college enrolment rate is four times as high.

Furthermore, nearly half of Shanghai's school-age children belong to migrant families and were effectively barred from taking the test: because of China's residence registration system, these students are forced to attend high school in their home provinces, where schools are often debilitatingly understaffed. Although students from 12 provinces took the test in 2009, the government only shared Shanghai's scores.

"The OECD has not disclosed if other Chinese provinces secretly took part in the 2012 assessment. Nor have Pisa officials disclosed who selected the provinces that participated," wrote Tom Loveless, an education expert at Harvard University, on a Brookings Institute blog. "There is a lack of transparency surrounding Pisa's relationship with China."

Wang Peng, a teacher in Wuhu, a city in Anhui province, said that his school's average class size is significantly larger than most in Shanghai, and that it cannot compete in terms of financial strength. Wang said he makes about £300 a month; teachers in big cities make twice as much. "As far as education methods go, there's not a huge difference [between Wuhu and Shanghai]," he said. "But the general educational environment, and the opportunities that students receive – those are really different."

Occasionally, reminders of the system's ruthlessness cause soul-searching. In 2012, pictures of a classroom of Chinese high-school students hooked up to intravenous amino acid drips while studying for the gaokao went viral on social media. Last May two teenagers in Jiangsu killed themselves after "failing to complete homework", according to state media. In 2012, a student emerged from the exam to learn that his mother had died in a car crash 12 days prior; the school and his relatives conspired not to tell him so as to not distract him.

Authorities recognise the problem. Last June the government issued guidelines urging schools to focus on students' "moral development", "citizenship" and "ambition" rather than their test scores.

Yet solutions remain elusive. One recently retired teacher at a Beijing middle school said she earns extra money by teaching an after-school cramming course called maths olympiad. The programme was designed as an advanced exercise for outstanding maths students.

In the late 1990s Beijing authorities barred grade schools from setting entrance exams, and some simply adopted maths olympiad scores as a substitute. Parents began to see the course as required, even if their children were uninterested or under-qualified. Although the education ministry has repeatedly cracked down on maths olympiad instruction, schools maintain the programme under different names, state media reported in 2012. Enrolment figures remain high.

"When maths olympiad first started, it had the right idea – it was a programme for students who were really interested," said the teacher, who requested anonymity because of the course's controversial profile. "There are a lot of kids without the ability who go to study this stuff, and it consumes their weekends, and their winter and summer vacations.

"These students aren't developing in a healthy way. This shouldn't be allowed to happen."