A legal opinion commissioned by the National Secular Society says the Church of England’s response to the government’s public consultation on marriage equality ‘confuses the issues’.

The Church of England’s response, which said gay marriages would “dilute” the institution and threaten the church’s role as state religion by making canon and state marriage laws incompatible, has already divided opinion within the faith itself.

Thousands have signed a petition to distance themselves from it and the Bishop of Buckingham spoke recently of a “sea change” of opinion within the Church.

But the National Secular Society said today that the Church’s use of “manifestly false” legal arguments was threatening to “obstruct democracy”.

Its commissioned legal opinion says the Church’s failure to distinguish between social, religious and legal institutions of marriage “confuses the issues”.

The NSS, which has been campaigning for a secular society for 145 years, sent the opinion, written by barrister and UCL law lecturer Dr Ronan McCrea to Equalities Minister Lynne Featherstone.

The opinion says: “Since the introduction of civil marriage in the Marriage Act (England and Wales) 1836, the law has envisaged the possibility that individuals who are not married in the eyes of the Church may be married in the eyes of the law.

“Divorced individuals who subsequently marry for a second time while their former spouse is still alive, are, for example, married in the eyes of the law and the State but not in the eyes of the Roman Catholic Church. The solemnisation of non-Christian and non-Jewish religious marriages is not recognised by the State, so in these cases generally both religious and State ceremonies are held.

“Quite properly, the State maintains its own definition of marriage and leaves religions to define marriage for their own purposes.”

Dr McCrea also questions the Church of England’s indication that the government’s proposed blanket ban on religious gay ceremonies may be overturned by the European Court of Human Rights. Further legislation would be required, it said, to protect the Church from carrying out ceremonies for gay couples.

The opinion continues: “Any successful court challenge would apply only to those denominations that wished to carry out same sex marriages. As an organisation opposed to same sex marriage, the Church of England would be unaffected.”

The document adds that the NSS’s “sincere commitment to religious freedom requires those religious bodies that wish to carry out same sex marriages to be able to do so”.

“Religious freedom and, the Society adds, the principles of secularism, dictate that religious bodies that do not wish to conduct same sex marriages should not be forced to do so.”

Keith Porteous Wood, executive director of the NSS, said today: “The evident desperation of some of the Church hierarchy to prevent same sex marriage at all costs has led them to put forward disingenuous and specious arguments in the form of manifestly false legal arguments. They have done so in the name of the whole Church, when it is well known that some in the hierarchy and probably the majority of those in the pews do not oppose same sex marriage.

“The Church has now added ‘obstruction to democracy’ to the long list of arguments in favour of disestablishment. To argue that the proposed change is inconsistent with continuing establishment is a foolish overplaying of the Church’s hand.

“Given that less than 2%, and falling, of the population are in CofE pews on a normal Sunday, the Church’s tenuous claim for continued establishment is already weak. But it is damaged irreparably by the barely disguised threat that establishment can bind the Government’s hands from making democratic decisions, particularly those giving greater human rights.”

The Church of England had no comment beyond its consultation response this morning.

The opinion can be read in full here.