It was meant to be the happiest day of their lives – a celebration of modern multicultural Britain at the biggest Sikh gurdwara (temple) in the Western world. On 7 August 2015, in west London, a British Sikh bride and her Polish Christian groom sat together and absorbed the religious blessings at their wedding ceremony. She wore a cream and red dress, while he wore a red turban, in keeping with Sikh traditions.

But that morning, 20 uninvited men were determined to put a stop to the wedding. They stormed upstairs to the main hall and demanded that the priests end the ceremony, hurling insults at people who objected. One of them told a priest that, if their demands weren’t met, he would get 1,000 of his friends to come to the temple within the hour. The police were called and eventually the couple were forced to proceed into a hurried ceremony, while the protesters watched and took pictures of them to publish online.

This was not an isolated incident. The next weekend an interfaith wedding in Lozells, Birmingham, nearly turned into a mass brawl after protesters tried to stop it and, again, the police had to be called. The following weekend, another wedding in Coventry only managed to go ahead after some negotiations with the disrupters. In each case, the bride was a Sikh woman and the groom a non-Sikh man.

Under the media radar, such disruptions of interfaith marriages at Sikh gurdwaras have become worryingly commonplace across Britain. In July 2013, a Sikh woman and her Christian husband in Swindon were locked out of their own wedding by 40 protesters, who afterwards posted a gleeful video online of the bride’s mother pleading with them to stop. When the BBC Asian Network looked into the controversy that year, its reporter met a family who’d had their windows smashed as a warning about an upcoming marriage. Most were too afraid to say anything in public.

But not Sim Kaur. One of the very few Sikh women willing to speak about her experience, she says: “Our gurdwaras are run by men and the protesters are all men. All the cancellations I’ve heard about have been of Sikh women marrying non-Sikh men or men not born into the Sikh religion and I doubt that’s a coincidence. I do believe it’s a faith issue, but it’s also about gender and race.”

A wedding party is refused entry to a Sikh temple in Swindon in 2012 (© SWNS Group)

Her wedding to her partner, Sam, was disrupted earlier this year, even though he had made an effort to learn about Sikhism and adopted Singh in his name, under guidelines laid out by the Sikh Council UK, an organisation set up in 2010 to deal with issues affecting the Sikh community in Britain and Europe. “Isn’t it better,” she asks, “that we teach our partners and their friends and family about this ceremony and invite them in, rather than building a wall and creating a divide?”

Sikh radicalism is rarely debated in the media. British Sikhs – who number about 400,000 – are largely seen as a model minority who aren’t embroiled in controversies or plagued by extremists as Muslims are. But scratch the surface and there are signs of a growing divide between the liberal and more conservative Sikhs here, and the controversy around interfaith marriages goes to the heart of the problem.

Until I posted several videos of wedding disruptions to my Facebook page last month, there seemed to be barely any debate about why they were happening. Immediately, I was subjected to a torrent of abuse and threats, but also heard from dozens of Sikhs (mostly women) who had faced a similar kind of intimidation. Most British Sikhs I have spoken to feel shocked and embarrassed that weddings in the UK are being disrupted in this way, but are usually too worried about the backlash from fundamentalists to say so openly – and it is a very British phenomenon. The controversy has barely affected India, home to 90 per cent of the world’s 20 million Sikhs, where interfaith marriages (especially to Hindus) are common.

One might, then, conclude that this issue was about race and the diaspora – but the experience of North America, where nearly a million Sikhs live, says differently. Amardeep Singh, associate professor at Lehigh University in Philadelphia, says that they have a more relaxed approach there, largely because there aren’t such concentrations of Sikhs as there are in London and Birmingham. “Sikh communities in the US are so suburban and spatially dispersed. Most of us commute some distance by car just to reach the nearest gurdwara.”

A Sikh wedding in 1965 (David Cairns/Express/Getty Images)

In the UK, then, we seem to be dealing with people who believe they have sufficient density of numbers to preserve some kind of cultural purity if they cleave to the example of the Sikh homeland (where, in fact, such fundamentalism is rare). However, those who support the disruptions say they are not opposed to interfaith marriages per se, but are only trying to enforce religious guidelines.

In 1950, Sikh scholars and priests in India agreed on a code of conduct, after multiple attempts, to define what it meant to be a Sikh and what obligations should be placed on followers. It stated that the Sikh wedding ceremony (the Anand Karaj) could only take place between two Sikhs of the opposite sex.

Shamsher Singh, of the National Sikh Youth Federation, says it objects to this religious ceremony being appropriated by non-Sikhs. “They can have prayers inside the gurdwara, they can have part of the function inside a gurdwara, just not the religious ceremony. That’s reserved for those of the Sikh faith.”

Others say this attitude ignores Sikh history. Amandeep Madra, co-founder of the UK Punjab Heritage Association, says that, until recently “Sikh traditions were highly pluralistic, with a willingness to learn and coexist with other concordant traditions. This is one of the most culturally appealing aspects of Sikhism in a modern, multicultural world. However, there has always been a more fearful voice that is threatened by the danger of being assimilated and indistinguishable from others.”

So the rise of Sikh fundamentalism in the UK isn’t just an attempt to enforce rules: it is also the expression of a worry among young rank-and-file males that Sikhs are becoming too integrated. To them, it is profoundly disturbing that a recent poll of members by City Sikhs, a 6,000-strong organisation representing professional Sikhs in the UK, should show an overwhelming majority in favour of gurdwaras allowing interfaith marriages.

To understand this, one must look to the history of Sikhi [the Sikh faith], the youngest of the world’s major religions, founded by Guru Nanak Dev Ji in the late 1400s. He was the first of 10 gurus (teachers) who left behind their collective wisdom in the holy scriptures, the Sri Guru Granth Sahib, also known as “The Living Guru”. In 1699, Guru Gobind Singh Ji decided to give Sikhs a visual identity to distinguish them from others. From then on, the Khalsa (baptised) Sikhs were required to carry five articles of faith at all times: uncut hair, a sword, comb, clean clothes and a metal bracelet. A large proportion of Sikhs remain unbaptised, freeing themselves from one or more requirements – they are usually called sahajdari, which could translate as “slow adopters” – but they still practise the religion in other ways.

And it is males at the heart of this issue. Many Sikhs see the bid to stop inter-religious marriages as an attempt by men to control Sikh women and stop them from marrying “out”. (Photofusion/Universal Images Group via Getty Images)

Since Sikhi was founded, its adherents in India have faced persecution from Mughal emperors, Hindu kings and the British Raj. Thirty years ago, thousands were killed by Indian troops in an anti-separatist attack on its Golden Temple, and in the pogroms that followed the retaliatory assassination of Prime Minister Indira Gandhi. Among some, this has led to a defensive mentality – exacerbated by worries that the religion is being diluted as new converts come into the fold – and this is what lies behind their radical puritanism.

So, while many Sikhs are integrating into British culture, others gravitate towards religion as their main primary identity. Shamsher Singh is one. “We’re dealing with complex issues of identity,” he says. “The intersection of our sense of self with coloniality has created this hybrid, stateless individual that struggles at every juncture with validation and having to constantly justify their beliefs and the practice of their religion to a Westernised audience. I’m living in an age where individuals on the periphery, with tenuous links to the community, are telling those of us who have committed to the Sikh way how we must interpret and practice Sikhi.”

Many worry that such attitudes will eventually shrink the community here, not strengthen it. Pippa Virdee, a senior lecturer on South Asian History at De Montfort University, says: “There has generally been a greater assertion of what it is to be Sikh in the last 10 to 15 years. That identity has become exclusive and serves to exclude people who see themselves as Sikhs but may not be practising. Increasingly, I feel we are told – often by men and by so-called leaders of the faith – what is a good Sikh. This will serve only to alienate people.”

As I can attest. After I posted videos of wedding disruptions, I was personally threatened and slandered on Sikh websites. People made up lies about me and I was accused of being a “traitor”. And my experience wasn’t rare. Two years ago, Kamalroop Singh, a turban-wearing and fully baptised Sikh, had his car windows smashed after he criticised Sikh fanaticism on a web forum. The incident left his children terrified and his wife ended up having a miscarriage, which the couple attributed to the stress. It wasn’t the first time he had been threatened and such incidents aren’t uncommon, he says. “They [Sikh radicals] really are just thugs who use the religion as their justification for intimidation and violence.” And last year Dr Gurnam Singh, principal lecturer at Coventry University, had to stop presenting a show on the Birmingham-based Sikh Channel after signing an online petition to stop “radicalisation of young, British-born Punjabi/Sikh males”.

And it is males at the heart of this issue. Many Sikhs see the bid to stop inter-religious marriages as an attempt by men to control Sikh women and stop them from marrying “out”. This sexist mentality surely has its roots in the (60 per cent Sikh) state of Punjab, which has among the lowest ratios of women to men in India due gender-selective abortions, infanticide, neglect of girls, rape and dowry-related murders. In some areas there are just 300 women to 1,000 men. There are laws against gender selection; there is an increasing number of educational campaigns; there are even media “stings “ in which doctors are filmed helping parents to abort female foetuses. Yet the ratio of girls to boys under the age of six has continued to decline.

Some Sikhs see the sexist attitudes in Britain and ask why there is an obsessive focus on interfaith marriages here when the larger Sikh community faces far more pressing problems. “If they so love Sikhi, why not question the high rate of female foeticide within the Sikh community as a hindrance ... rather than attempting to bar non-Sikhs from the marriage ceremony?” asks writer and journalist Herpreet Kaur Grewal.

Meanwhile, this controversy isn’t going to go away soon. The 2011 British Census found that 1.8 per cent of Sikhs (7,600 people) identified as white, while 1.2 per cent (5,000) identified as mixed-race, and it’s likely a large proportion of them do so through marriage to Sikhs, rather than conversion. If those numbers grow, and as some grow more liberal, the differences with more radical Sikhs will grow starker.

Jonathan Evans, who calls himself Jonny Singh, emailed me about his experience of moving closer to Sikhism after his marriage to a British Sikh woman. “If my wife and I were forced to abandon our Anand Karaj like couples in the UK are being forced to now, would I have felt the same about the vision of Sikhism as I do now?” he asks. “As humans we are shaped by our experiences. I would never have become a Sikh if I was not married in the gurdwara.”