The former leader of the Christian Peoples Alliance, Alan Craig, believes the Marriage (Same Sex Couples) Bill will lead to “new inequalities and discrimination” – and suggests it should include “polygamous marriages” for Muslims and Mormons.

Mr Craig, an ex-councillor for the London Borough of Newham, was nominated for Stonewall’s ‘Bigot of the Year’ award in 2012.

The year before he caused outrage by comparing gay equality advocates to the invading forces of Nazi Germany, dubbing them the “Gaystapo”.

In response, Mr Craig said: “The Bigot of the Year Award is a vicious name-calling Stonewall annual event that reflects more on the donor than the recipient.”

Earlier this week, in an article for Anglican Mainstream, Mr Craig wrote: “’Two people who love each other and are committed to each other should be allowed to get married whatever their gender. It’s an equality and human rights issue.’ This is the main argument advanced in favour of same-sex marriage.

“But it is a selective and specious argument, and in reality the bill does not create ‘equal marriage’ at all. Rather by changing the time-honoured definition of marriage from that between one man and one woman, it creates new inequalities and discrimination.”

Mr Craig continued: “It is notable for instance that the bill will allow two lesbians to marry but not two elderly spinster sisters. Like the lesbians, the sisters may love each other, be committed to each other and live together for many years, but the legislation does not follow its own logic and allow them equally to get married.

“And if the bill is about equality for minorities, why are the polygamous marriages of Muslims and Mormons excluded from it? And what about polyandrous marriages where there is one woman and two or more men?”

He added: “Further, there is an increasingly vocal minority demand for group marriage with multiple men and multiple women living in one so-called ‘family’. On what grounds are these minority ‘families’ excluded and discriminated against by the legislation?”

“So the bill is confused, illogical, irrational, unequal and creates new exclusions and discrimination against minorities. But worse, it completely ignores children. Same-sex marriage is about the interests of gay adults; children are not even mentioned in the legislation. Our children are our future, yet their rights and their welfare in marriages are completely blanked.”

The House of Commons will debate the Marriage (Same Sex Couples) Bill as part of its third reading on Monday 20 May and Tuesday 21 May.

It will then travel to the House of Lords for further debate, scrutiny and voting by peers.