As the TrawsCymru bus snakes along south Wales’s Taff Valley, we trundle past Gwaelod-y-Garth, Pontypridd and Nantgarw, leaving behind the ragged outcrops of Troed-y-rhiw and Pentrebach as we plough on north.

My family came from Europe as refugees to this land in the 1930s, and the sing-song place names speak to me as surely as the music playing in the cafés of Budapest or Berlin.

With the driver picking up speed, I look out over the wooded hills half clothed in low-flying clouds and still bearing blackened patches from the colliery waste that used to smother this landscape in my childhood.

I’m heading for Merthyr Tydfil, once a world-leading industrial hothouse, now scarred by waves of recession and downturn. It’s a place that’s had the stuffing knocked out of it many times but is still trying to keep a smile on its face. Today there really is reason to celebrate.

The old synagogue, once abandoned and derelict, is being redeveloped as a cultural centre for the whole community.

Though it’s still early days, the Foundation for Jewish Heritage is hosting an open day at the local Theatr Soar to build interest in the project.

An interior window of the synagogue

“We just didn’t know what numbers to expect,” says chief executive Michael Mail.

Tentatively, they put out a few chairs in the hall. He needn’t have worried. By the time I get there the place is heaving with curious locals, together with a good number who have driven up from the Jewish community in Cardiff and beyond, along with a dame, the local MP and a Welsh klezmer band.

A painting indicating the synagogue’s prominent presence in the town

I leave the buzzing theatre to climb the steep roads up to the old shul, and it’s immediately obvious that the challenge is immense. Dating from 1870 and the oldest purpose-built synagogue surviving in Wales, what was once a grand Victorian Gothic edifice looking uncannily like a grand castle is now a tottering wreck. Though the outside still looks sound, inside the three floors are all peeling paintwork, shattered mirrors and sheets of chipboard.

But it is loved. Examining the archive photos and architect’s projections I meet old friends Lionel Bernstein and Nettie Whitten, both aged 78, who grew up among the faithful of Merthyr Synagogue and were classmates at the local grammar school, housed in those days in Cyfarthfa Castle.

Her family were in the schmatte trade, where the non-Jewish employees’ conversation was seasoned with a scattering of Yiddish words.

Nettie told me: ‘They were such lovely happy times. It was it was a warm, friendly little community.’

Former Methyr Tydfil Synagogue members Nettie Whitten and Lionel Bernstein

Though now living in Cardiff, Nettie returns regularly to tend the Jewish cemetery. And what she’s really excited about today is that she’s arrived at the graveyard to discover floral tributes and cards marking Holocaust Memorial Day.

One reads: “Remembering the victims of the Holocaust and honouring those who survived,” and it is signed “The Residents of Merthyr Tydfil”.

She beams. “With all that is happening in the world, it is wonderful that the people of Merthyr do this,” she says, “and that’s what they were like when the synagogue was open.

“I didn’t come across antisemitism until I left. The local chapel and churchgoers of Merthyr, what lovely, respectful, just genuinely kind people.”

Klezmer band Klezmonauts at the open day for the shul

The last Jew of Merthyr was barber George Black, who died in 1999 aged 82 but had left town many years before. The synagogue – for a while repurposed as a church then a gym, and later a failed housing development – has long since been abandoned.

Merthyr Tydfil was a boom town of the industrial revolution, the biggest iron producer in the world in the early 19th century.

The first Jews arrived around that time and their community, growing in parallel with the town, peaked in the 1920s when the 400-seat hall of worship was packed on high holy days.

Inside the building in its heyday

As we saunter back down towards the town centre, Nettie and Lionel point to the shops that were Jewish owned in the 1950s and 1960s.

“That was Schwartz the furniture shop, that was one of two Jewish chemists, then there was the Shalowers wallpaper shop.”

A local cinema was Jewish-owned and the local GPs were all Jewish. At one time there were eight Jewish pawnbrokers in town.

“When you walked home from shul on Rosh Hashanah,” says Lionel, “you’d see signs in every other window saying ‘closed for the day’.”

Back at the theatre, Adrian Jacobs is proudly showing visitors some artefacts belonging to his family. Great-grandfather Zvi Himmelstein arrived here from Lithuania via Manchester, son Benjamin duly changing his family name to Hamilton. Zvi set up a successful jewellery shop, while Benjamin became a local solicitor and as coroner for East Glamorgan had the awful task of presiding over the inquests for the 144 people who died when discarded pit waste engulfed the village of Aberfan just five miles down the road in 1966. In so many small ways the history of this community is entwined with that of industrial south Wales.

A family photo belonging to Adrian Jacobs

The depression of the 1930s almost killed Merthyr but it staggered back to prosperity, helped by the opening of a Hoover factory and other light industry, until the recession of the Thatcher years laid it low once more. More recently, regeneration – mainly government-funded – has helped it crawl out of the doldrums.

“This is no Spitalfields,” says historian Chris Collier, “but Merthyr is finding its feet again.” He says the town needs the synagogue project as part of its upwards trajectory, and the hundreds of people flooding into the open day are a sign that the residents agree. The foundation has identified it as the most important Jewish heritage site in Wales, and shortlisted it as one of the most important endangered synagogues in the whole of Europe.

If the hoped-for injection of culture helps to regenerate the area, it might be history repeating itself. Back in the 1920s and 1930s the Dowlais and Merthyr Artists’ Settlements were intended to improve the lives of those hit by economic depression. Later my Uncle Heinz Koppel joined them, and along with a family zip factory down the valley in Treforest, gives me a lasting sense of connection to this place.

Methyr residents survey plans for the synagogue’s restoration

The Foundation for Jewish Heritage purchased the synagogue in 2019, securing half a million pounds from the National Lottery Heritage Fund, the Welsh Government and Merthyr Tydfil county borough council to develop the plans. King Charles visited while still Prince of Wales, celebrity patrons include comedian David Baddiel and Cardiff boy-made-Silicon Valley billionaire Sir Michael Moritz. An application for the £5 million needed to complete the project will be submitted at the end of the summer, and a decision is expected in December.

As the strains of clarinet and fiddle fade away, Philip Kaye, the Honorary Consul of Israel in Wales, offers me a lift back to the station.

I plan to return, because there’s something about this quirky little town and my own roots here that means that I’m keen to see the next chapter in the history of Merthyr and its historic synagogue come to fruition.