But, as the Executive and Parliament made clear when the legislation was introduced, civil partnership is not marriage, a fact that is clear to LGBT people also.

A marriage can be registered in a civil ceremony, or by an approved religious or humanist celebrant. For civil partnership, only a civil ceremony is available. Same-sex couples cannot have their partnership legally solemnised by a leader from their religion, or by a humanist celebrant, despite the fact that a number of faith bodies, as well as humanists, would like to offer this.

In other ways, civil partnership is equal in its legal effects to, but is separate from, marriage. Racially segregated education in the United States was once justified as being separate but of equal quality. The US Supreme Court, in the historic Brown v. Board of Education judgement, ruled that “separate but equal” can never be true equality.

Civil partnership is not equal to marriage; it is separate and symbolically different in a fundamental way. The present arrangements discriminate against same-sex couples, who cannot marry if they wish to, and against mixed-sex couples, who are denied access to civil partnership – which some mixed-sex couples would prefer to cohabitation or marriage. The current law also discriminates against transsexual people and their partners, because transsexual people cannot obtain gender recognition (which changes their legal gender) if they are married or in a civil partnership, and so must divorce first.

• The Scottish Parliament should legislate to repeal section 86(1)(a) of the Civil Partnership Act 2004 and section 5(4)(e) of the Marriage (Scotland) Act 1977, opening up civil partnership to mixed-sex couples and marriage to same-sex couples.