Two of the couples involved in a new legal fight for UK marriage equality have spoken about why they want equal access to marriage and civil partnerships.

The Equal Love campaign, organised by gay rights activist Peter Tatchell, will see four gay couples and four straight couples attempt to register for ceremonies they are not entitled to.

Instead of marriage, gay couples can currently have civil partnerships. These are not open to straight couples. However, some gay activists say civil partnerships are not good enough and that the two institutions should be open to everyone.

Rev Sharon Ferguson, who is an ordained minister of religion and chief executive of the Lesbian and Gay Christian Movement, said that she had been brought up to believe she would one day fall in love and marry.

She and Franka Strietzel are the lead gay couple in the legal action.

Rev Ferguson said: “Franka and I have been together for over two years and we recently started talking about having our commitment to each other recognised.

“Although I fully appreciate the benefits of civil partnerships, I don’t feel they are appropriate for us. As chief executive of LGCM, and also a pastor in the Metropolitan Community Church, I spend my life campaigning for justice and equality.

“The simple fact is that no matter how good civil partnerships are with regard to the legal protections and rights they provide, they are still a separate system that was put together to stop gay and lesbian people from being able to marry.

“Like most people in this world, we were brought up to believe that one day we’d fall in love and get married. This is what we want to do and our sexual orientation should not be an impediment,” she said.

The lead straight couple in the campaign are Katherine Doyle and Tom Freeman, who are both civil servants. The pair were supported by Mr Tatchell earlier this year when they tried to obtain a civil partnership at Islington registry office.

Ms Doyle said that she and Mr Freeman do not want to take part in the “patriarchal traditions” of marriage but wish to have their relationships recognised.

She said: “We have been together for nearly five years and would like to formalise our relationship. Because we feel alienated from the patriarchal traditions of marriage, we would prefer to have a civil partnership. As a mixed-sex couple, we are banned by law from doing so. By filing an application for civil partnership, we are seeking to challenge this discriminatory law.”

She added: “Our decision is also motivated by the fact that we object to the way same-sex couples are prohibited from getting married.

“If we got married we would be colluding with the segregation that exists in matrimonial law between gay civil partnerships and straight civil marriages. We don’t want to take advantage of civil marriage when it is an option that is denied to our lesbian and gay friends.”

The Equal Love campaign will see the eight couples attempt to register marriages or civil partnerships. When they are refused, they will take legal action.

The legal case is being prepared by Robert Wintemute, Professor of Human Rights Law at Kings College London.

According to Professor Wintemute, the twin bans violate the Human Rights Act in respect of Article 14 (protection against discrimination), Article 12 (the right to marry) and Article 8 (the right to respect for family life).

Mr Tatchell said: “In a democratic society, we should all be equal before the law. The ban on same-sex civil marriage and on opposite-sex civil partnerships is a form of sexual apartheid – one law for gay couples and another law for heterosexual partners. Two wrongs don’t make a right.

“Just as gay couples should be able to marry, civil partnerships should be available to straight couples.”