The 21 December is the fifth anniversary of the first civil partnership ceremonies in England.

This was a breakthrough moment in legal equality and social acceptance for same-sex couples.

Some same-sex couples  do not want marriage.  They are happy with civil partnerships.

We respect their feelings. But other lesbian and gay couples would like to get married. It is the universally recognised system of love and commitment.

I sympathise with heterosexual couples who don’t like the patriarchal history of marriage and the idea of being called husband and wife.  They would rather have a civil partnership instead.  The law should give them that option.

Peter Tatchell is coordinator of the Equal Love campaign – www.equalove.org.uk – which seeks to end sexual orientation discrimination in civil marriage and civil partnership law.

“Over the last two months, four same-sex couples were refused marriage licenses at register offices in Greenwich, Northampton and Petersfield. During the same period, four heterosexual couples were turned away when they applied for civil partnerships in Islington, Camden, Bristol and Aldershot,” said Mr Tatchell.

“All eight couples received letters of refusal from their register offices. We are using these rejection letters to challenge the exclusion of gay couples from civil marriage and the denial of civil partnerships to straight couples. Since there is no difference in the rights and responsibilities involved in gay civil marriages and heterosexual civil partnerships, there is no justification for having two mutually exclusive and discriminatory systems.

“Banning black couples from getting married would provoke uproar. The prohibition on gay marriages should arouse similar outrage.

“The ban on same-sex civil marriages and opposite-sex civil partnerships is a form of legal sexual apartheid – one law for gay couples and another law for heterosexual partners. Two wrongs don’t make a right.

“In a democratic society, we should all be equal before the law.

“Everyone should have a choice, either a civil marriage or a civil partnership, whichever they prefer. The current laws deny couples choice and discriminate on the grounds of sexual orientation. This what we are challenging in the European Court of Human Rights ,” said Mr Tatchell.

The news conference on Tuesday will be chaired by Peter Tatchell, and feature all eight couples and their legal advisor, Professor Robert Wintemute of the School of Law at Kings College London. He will outline the legal basis of the Equal Love challenge to the current proscriptions.

“Banning same-sex marriage and different-sex civil partnerships violates Articles 8, 12 and 14 of the European Convention on Human Rights,” said Professor Wintemute.

“It’s discriminatory and obnoxious, like having separate drinking fountains or beaches for different racial groups, even though the water is the same. The only function of the twin bans is to mark lesbian and gay people as socially and legally inferior to heterosexual people.”

I am confident that we have a good chance of persuading the European Court of Human Rights that the UK’s system of segregating couples into two ‘separate but equal’ legal institutions violates the European Convention. I predict that same-sex couples will be granted access to marriage in the UK. The government will eventually accept that it cannot defend the current discriminatory system.