A UK Supreme Court judge has given a robust defence of equal marriage in a speech delivered in Northern Ireland – where the measure remains illegal.

The Telegraph reports Lord Wilson of Culworth, a justice in the Supreme Court since 2011, made a speech to the Medico-Legal Society in Belfast on Wednesday.

The 68-year-old said that as a “committed member of the Church of England” he envied the “greater strength of traditional family values in Northern Ireland”.

He also said the decision of England, Wales and Scotland to legalise equal marriage would strengthen the institution.

Northern Ireland is now the only remaining part of the UK where marriage rights for same-sex couples have yet to be granted.

The Democratic Unionist Party has repeatedly vetoed debates on equal marriage in the Stormont Assembly.

Lord Wilson pointed out that same-sex marriage was “not a novel concept” and had been allowed in ancient Egypt and Republican Rome.

“Then, for the next 1,500 years, Christian doctrine … cast an irrational opprobrium upon all sexual acts other than procreative ones. In my view, the malign effects of the doctrine leave a residue even today,” he said.

“Far from destroying marriage, I think that to allow same-sex couples into it strengthens it; but in my view the most important benefit of same-sex marriage is the symbol that it holds to the heterosexual community … that each of the two types of intimate adult love is as valid as the other.

“The availability of marriage properly dignifies same sex love.”

He added that it was “not good enough” to suggest that same-sex marriage was inappropriate simply because it has traditionally taken place between a man and a woman.