Imagine if 40,000 Muslims gathered together in the south of England to swear a pledge of allegiance to Isis. Every major news outlet in the world would descend on the gathering and report that story. Now imagine what would happen if 40,000 Muslims gathered to pledge allegiance to a creed of peace to all and hatred to none, while they denounced violence and raised the flag of the UK. How many journalists would report that? I can tell you the answer, and it isn’t many. I know this, because as I sat in the Press and Media tent at just such a gathering, I was completely on my own.

The assignment was rather unusual. I was sent to interview a Jewish man about a Christian relic at a Muslim convention. What I experienced was nothing short of extraordinary. The Jalsa Salana convention, now in its 51st year, is a gathering of Ahmadi Muslims. The Ahmadiyya are the largest growing Muslim denomination in the world. Founded in 1889 by Mirza Ghulam Ahmad, who is revered as a Messiah by his followers, the group has expanded to more than 200 countries, and is led today by its Caliph, Mirza Masroor Ahmad.

For more than 100 years, they have been leading a peaceful revival of Islam, what they call the “true Islam”, and in the UK are responsible for building the first London mosque, in Putney in 1926, and the largest in western Europe, in Morden.

The Ahmadiyya are not without their critics. Many Muslims do not consider their teachings, particularly those in relation to a second Messiah, compatible with the Quran. In Pakistan, for example, it is illegal for Ahmadiyya to call themselves Muslim, and the Saudi authorities do not let Ahmadi Muslims perform the Haj to Mecca. Many have experienced persecution.

But there was no sense of that at the Jalsana convention. A huge site in Alton, Hampshire, had been transformed for three days into a sprawling mini village. Large white marquees were dotted around the site, which had separate areas for men and women. These tents were used for prayer or lectures; some were used to house a large bazaar selling everything from fresh food to books to clothing. There were also tents to showcase the work of Ahmadiyya humanitarian charities, while others were used for sleeping and serving meals.

Among the most charming displays was an exhibition of rare Qurans from all over the world, in a variety of scripts and designs. The collection was expertly explained to me by the curator’s 12-year-old daughter. Across the marquee from her, a huge replica of the Turin Shroud was displayed, and I spoke to one of the exhibit’s organisers, Barrie Schwortz.

“I was very nervous the first time I was invited here,” he told me. “I’m a Jewish American. What was I doing at a Muslim convention? But I’ve been back every year since.” Schwortz was one of the original photographers of the Turin Shroud when it was first scientifically investigated in 1978. Initially a sceptic, he has come to believe “almost 100 per cent” that the shroud was the one used to wrap Jesus’s body after the crucifixion. Ahmadi Muslims believe that Jesus was a prophet, that he was crucified, but that he survived for four hours on the cross after which he was revived from a swoon in the tomb. They believe that he later made his way to Kashmir where he died seeking the Lost Tribes of Israel.

I sat with a group of over 200 Muslim women while Schwortz explained the history of the shroud to them. It was a somewhat surreal experience to watch as Hijabi women listened attentively to this bearded Jewish man as he described his 40-year fascination with a Christian icon.

There were people attending the convention from over 100 countries. As I walked around the site with my guide, a trainee Imam from Calgary, I was introduced to guests from Pakistan, Ghana, Canada and Brazil. Many were wearing traditional clothing; bright African fabrics, intricate Indian headdresses and stunning Asian silks. At the centre of the site, a display of over 100 national flags fluttered in the strong breeze. In the centre, on a raised platform, the flag of the Ahmadiyya flew alongside the Union Jack, both guarded by four men. “The platform is guarded,” said my guide, “to show that we are prepared to defend our beliefs and our country, wherever we live. The two go together.”

The hospitality of my hosts was extraordinary. Heavy rain had produced Glastonburyesque areas of mud which my flimsy shoes were not prepared for. No matter. Within minutes of my arrival a pair of boots had been found in exactly my size. I was constantly asked if I was hungry, thirsty, or needed to sit. Before I knew I needed anything, it was provided. This, said my host, was all part of the Ahmadi commitment to hospitality to the stranger.

The convention lasts for three days and is entirely volunteer led. Everybody pitches in, from the young men manning the carparks, to the teenagers peeling potatoes for nine hours straight, and the young children on litter duty. I spoke to Sameera who has been coming to the Jalsana all her life. She told me that the only year she didn’t volunteer was when her baby was six months old. She didn’t enjoy doing nothing and has volunteered every year since.

I arrived on the final day, in time to witness a remarkable moment. As people gathered in the huge central marquee, with thousands more outside watching events on screens, the Caliph arrived. He kneeled on the ground and put out his hands. The men around him held on to his fingers, and those behind them held on to their shoulders. Each man held on to the man in front, to form unbroken lines of human contact, stretching from the Caliph out into the crowd.

The Caliph read out the pledge of allegiance, line by line, in a variety of languages, and the gathered crowd repeated after him. My guide pointed out that the men closest to the Caliph included those who had most recently converted. He added that he had attended the convention for 23 years and had never managed to get this close to His Holiness. His words reminded me of the mixture of awe and love that Chasidic followers often feel for their Rebbe.

After the pledge, which included a commitment to spreading peace to all and hatred to none, the men bowed in prayer. Slowly, some began to cry. Then sob. The sound of grown men crying reverberated around the huge marque. It was astounding. And rather humbling.

Then, just as quickly as he had arrived, the Caliph left, and the crowds began to disperse to other areas of the huge site. Before I left, I was introduced to the leader of the Ahmadi Youth Organisation in the UK. As he described the structure and activities of his organisation, I was struck by how similar it was to Tribe, RSY or any other Jewish youth organisation. And how many core similarities our communities share. It was a remarkable, and humbling, experience.

As I returned my press pass to the still-deserted media tent, I once again felt how skewed our media can be in regard to faith community relations. And proud to have played a small part in redressing the imbalance.