Back in June 2005, when José Luis Rodríguez Zapatero's socialist government amended the Civil Code to allow everyone to marry their partners irrespective of the gender of the two parties, the right-wing PP claimed it was 'unconstitutional' and put in a court appeal against it.

Mariano Rajoy – now president of Spain – said allowing same-sex couples to marry was 'unnatural' and 'went against the basic social and legal institution of marriage', which he said the Spanish Constitution described as a romantic union between a man and a woman.

He even when as far as to say allowing all-female or all-male couples to tie the knot in exactly the same conditions as mixed-sex couples 'flouted Article 10.2' which interprets the Universal Declaration of Human Rights and others relating to 'the protection of the family, women and children'.

But Zapatero – who famously challenged the PP leader to 'look a gay person in the face and call them a second-class citizen' – along with the homosexual community itself said 'flouting human rights' was exactly what banning same-sex marriage would do.

And it would also be, effectively, gender discrimination, and segregation on the grounds of sexuality, two situations forbidden by the Constitution.

Not only would it deprive them of the basic right of all consenting adult couples, irrespective of whether the parties are male, female or one of each, to pledge their love and commitment in a legally-recognised ceremony, but it would also leave them at a legal disadvantage in the case of inheritance, pensions, taxation, next of kin and many other areas, given that they would be considered 'live-in lovers' rather than 'a married couple' in the eyes of the law.

And not everyone on the PP party agreed with Rajoy's appeal against same-sex marriage.

President of the Region of Madrid, Esperanza Aguirre, publicly stated her support for all-female and all-male marriages, whilst the current minister for justice and then mayor of Madrid, Alberto Ruiz-Gallardón, said he could not see any reason why it was unconstitutional – and in fact, has married numerous same-sex couples in the last seven years.

Gay Pride in Madrid had what they called a 'shameful' appeal that was 'an attack on human rights and social freedoms' as its central theme.

Politicians, such as Elena Valenciano (PSOE) and Rosa Díaz (UpyD) joined the march and shared the messsage, as did union leaders Ignacio Fernández Toxo and Cándido Méndez.