Ahmadi Muslims say they want to redefine the public image of Islam in the western world.
But the majority of Muslims object to the community describing themselves as followers of Islam, saying they are even banned from its holy sites.
But up to 30,000 adherents of the faith will debate their future at the event in Surrey, say community leaders.
Ahmadi Muslims, who originally hailed from the northern India area of Punjab, believe that Mohammed was not the final prophet sent to guide mankind.
Instead, they believe that a further prophet emerged during British rule of India in the 19th century.
Mirza Ghulam Ahmad, who died in 1908, is regarded by Ahmadis (also known as Ahmadiyyas) as the promised messiah. Mainstream Muslims regard this as blasphemy.
The movement, established around the world, has a major base in London with a recently completed principle mosque.
The weekend conference is taking place at its “Islamabad” grounds near Tilford, Surrey.
But there are intense disputes about the strength of the community.
While Ahmadis say they have 200 million followers, mainstream Islamic scholars say this is a massive exaggeration. They claim there are at best 10 million Ahmadis.
The Ahmadi community faces restrictions in many Muslim nations, saying followers are constantly persecuted. Amnesty International has also recorded members of the community being killed or imprisoned for their beliefs.
In 2000 an eminent Pakistani surgeon and member of the community was shot dead, a killing Ahmadi leaders blamed on extremists.
‘Ugly and awful image’
Hadhrat Mirza Masroor Ahmad, world head of the community, said: “What has given Islam a bad name is an ugly and awful image of extremism presented, whether knowingly or unwittingly, by some Muslim groups and organisations.
“The stand of the Ahmadiyya Muslim community is that the teaching of the Holy Koran promotes peace. We have to take this message to every corner of the world.”
Rafiq Ahmed Hayat, head of the Ahmadiyya’s UK association, said: “Our mission is to allow people to see Islam for what it is – the perfectly peaceful religion.
“That can only be done if the followers set an example by being strong in their own faith yet tolerant and understanding of other faiths.
“We urge like-minded Muslims of all sects to follow suit and to rise up against the fanatics by demonstrating in a practical way that Islam is a friend, not a foe.”
Opposition from other groups
Mainstream Muslim leaders say they regard Ahmadis in a similar way to how mainstream Christians regard Mormons: while the sect is based on the teachings of Christ, its practises are so different other Christians do not accept them as part of the family.
Ahmadi Muslims are not allowed to enter the Islamic holy sites of Mecca and Medina in Saudi Arabia.
In January 2004 Bangladesh’s religious affairs ministry banned the Ahmadi community from publishing, sayings its opinions were hurtful to the majority of the nations Muslims.
But leaders of the community in Bangladesh said the government had given in to religious terrorism.