The Church of Jesus Christ of Latter-day Saints wants the B.C. Supreme Court to stop fundamentalist leader Winston Blackmore from using its name.

Blackmore is the leader of a Bountiful-based 500-member polygamous sect, based on the teachings of Mormonism’s founder Joseph Smith.

The 15-million-member mainline church (colloquially known as the LDS or Mormons) rejected polygamy in 1890. In a lawsuit filed Wednesday, it alleges that Blackmore registered the name, Church of Jesus Christ of Latter Day Saints Inc., in 2010.

The LDS found that out when it tried earlier this year to register the name, which it says it had used in B.C. since 1838, and was blocked. (Before its incorporation in January, the Canadian branch of the Utah-based church was a trust set up under the laws of Alberta, although it had trademarked its name in both the United States and Canada.)

The Mormons allege Blackmore “misappropriated the names, identity and reputation” of the mainstream church.

The lawsuit’s allegations have not been tested in court and Blackmore has several weeks to file a response.

In its notice of civil claim, the LDS notes: “The church and the plaintiffs have nothing whatsoever to do with those practicing polygamy today. Any church member who is found to be practicing polygamy is excommunicated, which is the most serious penalty the church can impose.”

The suit goes on to allege that Blackmore has made statements “tending to discredit the wares, services or business” of the LDS, “directed public attention to the defendant’s wares, services and business in such a way as to cause or is likely to cause confusion,” and passed off his own products and services as those of the mainstream church.

The LDS wants the court to order Blackmore to give up the corporate name and “deliver up or effect destruction upon oath of all signage, brochures and other materials of any kind in possession, custody or control … that may offend the injunctive relief sought.”

The LDS says it has 30,000 members in 79 congregations in B.C. and more than 190,000 members across Canada.

Blackmore sect represents mostly members of his large, extended family in B.C., Idaho, Utah and Arizona.

Before forming his own group, Blackmore was the bishop of the Fundamentalist Church of Jesus Christ of Latter-day Saints.

After his excommunication by its leader Warren Jeffs, who is now serving a life sentence in Texas for sex crimes committed against children, Blackmore registered the name “The Fundamentalist Church of Jesus Christ of Latter Day Saints” in 2008 in British Columbia.

He changed the corporate name to “The Church of Jesus Christ of Latter Day Saints Fundamentalists Inc.” in January 2010 then changed it again in May 2010 to “The Church of Jesus Christ of Latter Day Saints Inc.”

dbramham@vancouversun.com