MPs who vote for Cameron gay marriage pledge will be punished at election time London, : MPs who vote for David Cameron's gay marriage pledge will be punished at the general election, says the Society for the Protection of Unborn Children (SPUC) www.spuc.org.uk a leading pro-family campaigning group said today.

SPUC was responding to Mr Cameron's speech, reported by The Telegraph this morning in which he promised to enshrine same-sex marriage in law before the next general election in 2015.

John Smeaton, SPUC's chief executive, commented: "There are numerous reports that the Conservative party is already losing huge numbers of voters, members and activists because of Mr Cameron's foolish support of same-sex marriage. SPUC and its colleagues in many pro-family, Christian and Muslim groups, representing countless thousands of supporters and activists up and down the country, will ensure that same-sex marriage becomes a big general election issue, especially in marginal constituencies."

"Mr Cameron's speech reveals that his understanding of marriage and religion is woefully simplistic and ignorant. His mantra of 'equality' totally ignores the nature, history and role of marriage, which is the union of one man and one woman ordered towards the procreation of children."

"Redefining marriage to include same-sex couples is outside Mr Cameron's remit as a political leader. The family - not the government - is the first and vital cell and source of human society, and is therefore a pre-political institution. By seeking to redefine marriage, Mr Cameron is also seeking to redefine the family, which is based upon marriage between one man and one woman. Mr Cameron is clearly doing his best to copy Tony Blair as a social engineering guru", concluded Mr Smeaton.

SPUC's position paper on same-sex marriage explains why SPUC, as a pro-life campaigning organisation, campaigns against same-sex unions. John Smeaton, SPUC's chief executive, can be contacted on 07785 325808 or 020 7820 3127.