The public school is among six village schools in the border catchment areas of Yuen Long and North District (covering Sheung Shui, Fanling and Sha Tau Kok) which were allocated HK$114.5 million between them for expansion and refurbishment in the past year.

It's a reversal of fortunes for village schools, which bore the brunt of closures in a government drive to consolidate underutilised schools. Eighty six publicly funded primary schools were forced to close between 2005 and 2012 because they could not enrol the minimum 16 students for two consecutive years. Of the 100 village schools in operation a decade ago, only about 10 remain.

But a swelling stream of cross-border students in recent years - children born in Hong Kong to mainland parents or who live on the mainland with Hong Kong parents - has now given the surviving schools an enormous boost. Shan Tsui Public School in Sha Tau Kok, for example, now has an enrolment of more than 200 pupils, 90 per cent of whom are cross-border children, says principal Siu Hong-cheung.

The school was given a complete overhaul last year to meet its growing needs. In the past it only had three classrooms and a playground; there wasn't even a school hall.

Following a HK$20 million makeover last year, it now has a library, activity room, computer room and six new classrooms. This expansion has enabled Shan Tsui to switch to a full-day system this year, compared to the past when it ran three half-day classes in the morning and another three in the afternoon, Siu says.

Even so, he criticises the government for being slow to respond to the pressure on school places in North District, resulting from an influx of cross-border students.

"Six village schools formed a union six years ago to ask for more resources but the government ignored us. They closed too many schools in North District and tackled the problem of shortage of school places too late," Siu says.

The number of cross-border students studying in public primary and secondary schools has almost doubled from 4,988 in 2009 to 8,764 this year, Education Bureau figures show. Many clustered in North District, where classrooms were soon packed to capacity.

This resulted in 400 children seeking places in the district being allocated outside the school net for the new academic year, provoking an outcry from local parents whose children faced a long commute to class in other districts.

As a stop-gap measure, the bureau reopened premises in Sheung Shui once occupied by Fung Kai No2 Secondary School, to offer about 100 places for parents dissatisfied with their children's place allocation.

As North District councillor Lau Kwok-fan sees it, this unhappy state of affairs stems from a lack of planning by the government. "The influx of cross-border kids could have been foreseen by looking at population trends," Lau says.

"Without mainland residency, Hong Kong-born [children] of mainland parents are denied access to mainland schools, which means most must return [to Hong Kong] when they reach school age. The demand for school places in North District will lessen later as mainland mothers without a local husband can no longer give birth here," Lau says. "But [the pressure] will certainly get more severe in the next few years."

Hong Kong births to mainland parents have exploded from just 2,070 deliveries in 2003 to 32,653 in 2010. A government poll at Immigration Department birth registries between 2007 and 2009 pointed to a looming need for school places: of 12,000 parents surveyed, most said their children would return to Hong Kong between the ages of three and 11.

Nevertheless, an Education Bureau spokesman says it is difficult to accurately project the demand for school places in North District because "whether and when cross-boundary students would come to Hong Kong to study is very much a personal decision of their parents".

For village schools, it has been a long and bitter struggle to stay alive. Shan Tsui Public School, set up in 1958 as a private institution to cater to children in Shau Tau Kok, faced its bleakest period in the '90s as the settlement's population began to shrink after the '80s.

"In 1992, we enrolled only 10 students," recalls principal Siu. Prospects began to improve about a decade ago, when it began to take in cross-border children. "As we are situated at the border [Chung Ying Street forms part of the border between Hong Kong and the mainland], the children can get to our school in 10 minutes whereas it would take them an hour to travel to Sheung Shui."

But the school had to take extraordinary measures to stave off closure, says Siu, who has taught at Shan Tsui for more than 20 years.

"We offered English classes on the mainland for parents. Our parent-teacher association reached out to mainland women's groups. We organised talks on parenting. We even got lawyers and social workers to provide consultation for mainland parents about cross-border marriage issues."

At Ling Ying Public School, where 70 per cent of students are from the mainland, Chu reports similar experiences

"We did a lot of promotion work to survive, like reaching out to mainland kindergartens," he says. "Now that admission pressure has lifted, we can concentrate on striving for quality education."

The mainland-based students come to school by bus, and teachers are sent to the checkpoints to make sure there are no problems during the crossing. When pupils fall ill, meanwhile, it is staff who take them to doctors as not all mainland parents have year-round border permits.

Unlike the cross-border-centric schools, Pat Heung Central Primary School in Yuen Long found a new lease on life when it began catering to ethnic minority students 10 years ago.

Built by Pat Heung residents on their own land in 1921, the school occupies a grade three historic building with six classrooms and a small library. As closure loomed, it joined up with another village school and began taking a multicultural route in 2003.

Now, just 20 students in the school are local Chinese. The remaining 171 pupils are children from Pakistan, Nepal, Sri Lanka, the Philippines and Africa (five are refugees from the Congo and Somalia). To house the swelling student body, construction has begun on a two-storey teaching block.

Classes are conducted in four languages - Urdu, Nepali, English and Chinese - and there are special foundation classes to help non-Chinese students master the local language.

The village schools have shown remarkable resilience, says Lo Wai-yin, an assistant professor at the Hong Kong Institute of Education.

"Many are labours of love by villagers who raised money to build a school to serve their children. Not only were they learning institutions, they were also a cohesive force that drew the village together," says Lo, who conducted a study of 56 rural schools between 2006 and 2009.

"But the Education Bureau only saw them as statistics when they closed them. With the schools gone, many villagers lost a place for communal discussion."

While she is relieved that village schools are now enjoying a revival, Lo frets that many will lose their unique identity. "Village schools used to run small classes. Now their class size is over 30, just like mainstream schools," she says.

Lo says the government should consider reopening strategically sited village schools such as Ku Tung Public Oi Wah School in Sheung Shui. Just a 10-minute bus ride from the Huanggang checkpoint, Oi Wah closed in 2007. But the premises, which includes a playground and auditorium, are still quite new, Lo says.

"If such schools were reopened, other village schools wouldn't have to take in so many pupils and can continue small-class teaching."

That prospect is uncertain. The bureau expects demand from cross-border children to fall following the "zero birth" ban on mainland mums. During this transient period, the bureau will adopt "flexible measures", including borrowing school places from other districts, and making use of unused classrooms and vacant school premises, the spokesman says.