Hidden between the close-knit terraced roofs of inner-city Cardiff are the white domes of a cultural gem.

Domes of the temple in Mardy Street, Grangetown

Prayers at the Shree Swaminarayan temple in Merches Place, Grangetown, begin at sunrise just after 7am. Step into the long prayer room, a former nightclub floor, and you hear the jangling of bells and musical chanting.

The temple is the third biggest for the Swaminarayan Hindu denomination in Britain, after two in London, and the only one of its kind in Wales. Yet without its bright white walls and distinctive domes, some built from fibre as recently as 2005, it would barely stand out from the Victorian homes and warehouses which surround it.

Sixty two-year-old Naram Patel is a freelance tax investigator – but in his spare time he has been the temple’s president for 27 years.

He saw it through its move from a building across the road, which was once a synagogue and has now become a pentecostal church, to its £250,000 home in 1993. Since then it has seen an £800,000 refurbishment, with the temple’s loyal attendees knocking down a huge section and building it again themselves.

“We have everybody in our community,” said Mr Patel, who has a son, two daughters and six grandchildren. “We have quantity surveyors, bricklayers, engineers, you name it. The only people we couldn’t find were factory workers.

A worshipper in the temple

“We did it on the weekends, working flat out from 7am to 8pm. Any given weekend there would be up to 50 people here. All the labour was free. Younger people would turn up to look and they wanted to work, but we couldn’t use them – it would have been child labour.

“It was tiring but it’s the energy we have built in us.”

Now the rebuilt temple features ornate idols set in wooden screens. Men in colourful, patterned robes walk up and down with candles and every year during Diwali, the festival of light, 1,000 worshippers from all over Wales flock to the huge rooms beneath the upstairs temple to feast on lunch and dinner provided for all.

And during the Aarti ceremony every morning and evening, worshippers sing and pay tributes to the idols. Selected members are allowed into the inner sanctum, below a low wooden fence, to touch the idols. Before and afterwards, they are not allowed any human contact. But Mr Patel said despite all the conventions, the doctrine is simple.

“There is a single message in the songs,” he said. “You should live a good life and a neighbourly life, and be sure you are a good citizen of the country you are in.”

Idols inside the temple

Men prostrate themselves on the floor while women, behind a separate screen, stand respectfully and sing. Although the temple welcomes worshippers from all denominations, its practices are conservative. “If you pray all your concentration should be towards God,” said Mr Patel. “You don’t need a distraction, so we don’t want to pray together.

“When we pray, we also ask for strength to live in a society which is strange to some of us. Some of the older people don’t speak English. It is hard for them. If they don’t work it can be difficult to find a way of getting on.”

Volunteers at the temple give English classes to the elders who speak Gujurati, and classes in Gujurati to the teenagers who speak English. Children play in a full-sized sports hall on the ground floor and there are two or three traditional weddings per year.

Women at morning prayers in the temple

But those who do not follow the faith are also given support. In the Samaj social centre next door, people from the community learn traditional dancing and play Indian instruments.

Mr Patel said: “It’s more important for people to stay part of the community, even if they don’t believe.” Sixty per cent of the attendees are from Grangetown, including Mr Patel, who lives just yards away in Dinas Street, and a warm community feel radiates from the bustling prayer room.

The temple has become popular with schools too, where students are taught yoga and play musical instruments. The Cathedral School, Llandaff, brought a class to the building on Thursday. But they saw schools from as far afield as Denmark last year, and in June will be visited by pupils at the exclusive Westonbirt girls’ school in Gloucestershire. Police cadets even visit to learn about Hindu manners and culture.

Meanwhile on the day I visit, it is the birthday of Hindu god Shree Nar Narayan. A reincarnation of the supreme god Suwami Nar Narayan according to the faith, he is given a dress of flowers to celebrate the occasion and sits on a wooden swing.

I pause for a few moments. Among the singing and the jangling of instruments, it makes, if only for half an hour, an oasis in the midst of a bustling Cardiff morning.