In order to marry Prince Harry, Meghan Markle is soon to be baptised and confirmed into the Church of England. This is to satisfy her soon-to-be grandmother, who takes her title of Supreme Governor of the Church incredibly seriously. So much so in fact that the Queen didn’t even attend her son’s civil wedding ceremony – only showing up for the religious blessing of Charles and Camilla.

As divorcees, the former Archbishop of Canterbury Rowan Williams refused to let Prince Charles and the Duchess of Cornwall marry in Church. The present Archbishop of Canterbury, Justin Welby, has no such qualms about the remarrying of divorcees.

But this again highlights the close and interwoven relationship between the Church and British monarchy and other state institutions.

As a new report from the National Secular Society rightly points out, this unsatisfactory and outdated relationship will be further highlighted at the coronation of the next British monarch. The initiation rite will be held at Westminster Abbey. With the world looking on, the Archbishop of Canterbury will ask the future monarch the following questions:

• Will you to the utmost of your power maintain the Laws of God and the true profession of the Gospel?
• Will you to the utmost of your power maintain in the United Kingdom the Protestant Reformed Religion established by law?
• Will you maintain and preserve inviolably the settlement of the Church of England, and the doctrine, worship, discipline, and government thereof, as by law established in England?

The ceremony, echoing the divine right of kings, will seem outdated to many, and within the context of modern Britain, it will also be alien to the majority in terms of what it seeks to represent. What message does it send out when our Head of State, ceremonial or otherwise, is the chief cheerleader for one particular denomination within the Christian religion?

It’s easy to see how, by upholding these commitments, the monarch serves the established Church, but it’s hard to see how they serve the nation. Whatever your views on monarchy v republicanism the head of state’s official accession should be inclusive and representative of the heterogeneous state the will be heading. This ceremony will make Britain look like a museum to the past and a bastion of religious privilege, where non-Anglicans are tolerated but decidedly relegated to second-class citizens. How will that aid social cohesion?

We talk a lot about inclusivity in Britain and pretend to cherish our rich diversity, but when it comes down to it, our state institutions are still clubs for Christians. Our head of state is ‘Defender of the Faith’, Church of England clerics sit ‘as of right’ in our legislature, parliamentary business begins with Anglican prayers, Bishops lead our national civic occasions, and ‘broadly Christian’ worship is required in all schools. It would be naïve to think this supremacist attitude doesn’t trickle down and pervade wider society. If diversity really is “a source of strength and pride” for us, as the PM insists, then it’s time to practice what we preach.

Britain has changed beyond recognition since the coronation of Queen Elizabeth II in 1953. Today, we’re one of the most religiously diverse, and least religious, countries in the world. With society at risk of fragmenting along religious lines, the time has come to set the wheels in motion to becoming a modern secular state.

Nobody would suggest that disestablishment is the panacea to cure all ills, but would for once enable Britain to have the idea of equality embedded in it. It would certainly make the state more representative of Britain’s changing religion and belief landscape, and could help foster a sense of national identity – a cohesive whole – that religious diverse countries with a state religion can never achieve.

One major obstacle is of course that disestablishment is not generally politically salient. Politicians fear to tread there. But sooner or later we’re going to have to face up to the reality that Britain isn’t a Christian country – and do something about the ties that bind.

Those who enjoy the benefits of religious establishment are also likely to frustrate the process. They receive tangible benefits from it and will defend it energetically. This of course includes the bishops, whose seats in the House of Lords give them significant political power and prestige.

Rowan Williams has stated that disestablishment would be ‘by no means the end of the world’, while his successor, Justin Welby has claimed that it would ‘just be another event in a very long history’ of the Church. But make no mistake, the Church is unlikely to give up its privileges willingly. The changes must be forced through politically.

Religion of course has a place in our society for those who want it, but on terms of equality, not privilege. There is a responsibility on all of us that want to live in a fairer, more egalitarian society to challenge religious privilege and push for disestablishment. Change can happen, but first Britain must summon up the will.