There’s no sign nor sound of sheep in Harlesden. Children playing on the streets do so in the shadow of tower blocks, not abandoned mine shafts. And while there are poems on the Underground, nothing has been written praising the lyrical flow of the North Circular interchange.

There is, in fact, little that is obviously Welsh about Harlesden. But it was to this part of north-west London that Matthew Davies chose to come when looking for his first teaching job, one that offered a quintessentially Welsh experience.

This term, he begins his second year as key stage 2 teacher at the London Welsh school, the only Welsh-speaking school outside Wales. Dwarfed by a more conventional primary next door, the two-room school could have been lifted intact from a village in rural Wales. “The school I taught in while I was doing my teacher training was in a rough area of south Wales, and I had a class of 30 pupils,” the 34-year-old says. “It was more like crowd control than teaching. Here, I teach five pupils full-time. This is what it’s all about.”

Here, the entire full-time roll amounts to only 11 pupils, although the school takes part-timers on Friday, when pupils who attend other primaries during the rest of the week push the number up to 29, and teaching is entirely in Welsh.

On the playground wall, the words “Ysgol Gymraeg Llundain” (School Welsh London) serve as identification for any Welsh-speaking passers-by. Inside, wall displays are labelled entirely in Welsh. Infants Bryn, Ieuan and Angharad sit colouring at a table, working their way through a drawer labelled papur sgrap. Above them, an unmistakably significant row of red dragons hangs on a wall. And, at the end of the day, while parents wish each other “Prynhawn da” in the playground, the 11 children who comprise the school’s entire full-time roll call bow their heads in prayer, offering ddiolch to Duw above.

Most Welsh teachers decide to work in a two-room schoolhouse only after careful consideration. For any young, newly qualified teacher there is an element of necessary compromise: the career satisfaction of small class sizes and individualised learning at the expense of the personal advantages of big-city living. But, for Mr Davies, there has been no such weighing up of priorities. “I have all the advantages of a teacher in a rural school, but I live in London.”

He also has the advantage of teaching in his mother tongue. The child of teachers, Mr Davies grew up speaking Welsh to his mother and English to his father. As a result, he says, he has developed an innate ease with languages. It is a skill he has also observed in his pupils. “We can look at an English passage and discuss it in Welsh,” he says. “Using language skills is natural for them. They’re used to flicking between them. And being bilingual helps them in French lessons, too. They’re quick to pick it up.”

The independent primary school was founded in 1958 to provide the children of London-based Welsh emigrants with a traditional education, but it is not just its size that links it with the village schools of its spiritual homeland. Like many small schools, it has suffered recently from a diminishing roll. And, like its village counterparts, it has had to contend with threats of closure.

In 1999, following the closure of the Willesden-based Welsh Presbyterian chapel that housed it, the school was left without premises. With no alternative site available, parents were reluctant to keep their children at the school. Pupil numbers fell to six in 2000. But, shortly before the school was to shut, Brent council stepped in, offering the use of a former nursery building adjoining Stonebridge primary school. Though in the shadow of the larger school, the new premises are self-contained, with their own gate and playground.

“The school is a little island,” says headteacher Elizabeth James. “Welsh people living in London want their children to know where they’re from.

They want them to feel they’re part of the Welsh family, to be culturally aware of their country of origin.” In most pupils’ homes, at least one parent speaks Welsh.

For its pupils, who at primary age have not yet learned to be embarrassed by difference, the linguistic uniqueness is to be relished. “I like speaking Welsh,” says 10-year-old Hannah Garrard, without hesitation. “It makes you feel a bit special. And you can talk about other people, and they don’t understand.”

“Some of my relatives don’t even speak it,” says eight-year-old Dewi Brady.

“Even in Wales, there’s actually not that many people who speak Welsh.”

“Most of them go back to Wales regularly,” says Mr Davies. “But even when you have a granny who speaks Welsh, it’s not the same as having other youngsters to talk to.”

The London Welsh school is part of a burgeoning Welsh-medium education sector. Welsh language resources are proliferating, publicised at national conferences, where teachers exchange ideas and methods. But, east of the Severn, there is little call for such resources. “Everything is in Wales,” says Mr Davies. “If we want resources, we have to physically go and get them.” Because of the size of the school, it’s difficult for the two teachers to get to conferences, and supply teachers rarely speak Welsh, so they must cover for each other.

Nevertheless, advances in technology mean they can tap into online resources, and they can also access the Welsh language television station, S4C. The school uses email to write to two Welsh medium primaries in Wales, and competed for the first time this year in the Eisteddfod, celebrating, music, poetry, history and culture. In previous years, the school has taken a stall at the event.

Of course, Mr Davies can always use his family connections. His sister, also a primary school teacher, took the more conventional decision to stay in Wales and is happy to offer resources and advice. (Sympathy is less forthcoming given his pupil-teacher ratio of 1:5. “My whole family laugh at me when I say I have reports to write.” He concedes there’s much less paperwork and marking, but points out that he has to plan for three year groups at once.) At key stage 2, maths and science are taught in English, to prepare pupils for London secondary schools. But this year, for the first time in its history, London Welsh pupils will sit key stage 2 tests, a decision reached with some trepidation. The school follows the education curriculum set out by the Welsh Assembly in 2001. As in Wales, therefore, there are no tests at the end of key stage 1: seven-year-olds are measured by teacher assessment alone. So the key stage 2 results will provide new data by which the school can be measured.

“Obviously, there’s a lot of pressure,” says Mr Davies, who will prepare key stage 2 pupils for the tests. “But it could be a good marketing tool for the school. We have two pupils taking the exams. If both do well, we’ll have a 100 per cent pass rate.”

And, adds Elizabeth James, successful results may help the school financially. Brent council has determined that the Welsh do not qualify as an ethnic minority group, so the school receives no local authority funding. Its pound;100,000 running costs are met through a variety of sources. Parents pay pound;600 termly tuition fees, and the London-based Welsh community supports the school through fundraising events. But the majority of the costs are met through an annual grant of pound;27,000 from the Cardiff-based Welsh Language Board. This is dependent on a series of attendance and achievement targets.

One target is to get the roll up to 25, “which isn’t feasible within the next two or three years”, says Ms James. “Early years is looking healthy, so numbers will go up significantly in the next four years. But there’s a lot of pressure on the children sitting exams.”

Hannah Garrard and Dylan Brady, the two pupils who will sit the key stage 2 tests this year, seem unfazed by the thought that the long-term future of the school may depend on their academic performance. They have more immediate concerns. “When you’re in Year 6, you have more authority, so it’s harder work,” says Dylan. “And secondary school next year will be weird. People will be interested in you because they won’t speak Welsh. My brother had to do a special project on Wales, and they’ll probably ask me to do one as well. It’s quite cool being bilingual, but sometimes it means more work.”

London Welsh school: 020 8965 3585