The far-right founder of an anti-equality group which opposed same-sex marriage, women’s rights and the Equal Rights Amendment has died aged 92.

Phyllis Schlafly, founder of the Eagle Forum, passed away at her home in Missouri from undisclosed causes on Monday (September 5).

The ultra-conservative group, which boasts having 80,000 members and was set up by Schlafly in 1975, made the announcement about her death.

Described as one of the most polarising figures in American politics, she organised a number of grassroots campaigns against communism, abortions and the Equal Rights Amendment. Her activism helped conservatives reinforce their views for almost two decades.

In the 1960s, her self-published book, ‘A Choice not an Echo’, sold more than three million copies and helped plant the seeds for a conservative revival in the 1980s under Reagan.

In the 1970s she was described as being like a “religious heretic” by the left, for opposing the Equal Rights Amendment.

Having been approved by both houses of Congress and adopted by 35 states, it lost steam with only three states to go because of Schlafly’s mobilisation of conservative women.

It failed to meet the deadline set by Congress, including an extension, and was ultimately defeated by 1982.

Schlafly eventually extended the Eagle Forum’s remit to including opposition to same-sex marriage, once claiming that “attacks on the definition of marriage as the union of one man and one woman come from the gay lobby seeking social recognition of their lifestyle”.

This was despite her son, John, who worked for her, coming out in 1992.

He claimed his mother was not anti-gay and that “the concept of family values should not be threatening to gays and lesbians”.

She said the press coverage of his homosexuality was an attack on her.

A number of conservatives have rushed to social media to pay their respects to Schlafly.

Former US Vice-Presidential hopeful Sarah Palin, said: “She went down swinging!”

Adding that she was “Iconic” and “heroic”.

Mike Huckabee, who ran against Trump for this year’s nomination, said Schlafly changed his life.