When the Queen died, she was actually a Presbyterian. That’s because she was in residence at Balmoral, and all British monarchs change their religious identity when they arrive in Scotland. They board the Royal Train at King’s Cross as Supreme Governor of the Church of England, responsible for appointing bishops whom it teaches are successors of the Apostles. By the time they arrive at Waverley they belong to a Church which has no bishops and whose only Supreme Governor is Jesus. King Charles, who succeeded to the throne in Scotland, did so as an ‘ordinary member’ of the Kirk – which, as the Royal Family’s website explains, is the only religious status that the sovereign enjoys north of the border.
Many Christians find this arrangement very odd indeed. They include a fair number of Anglican clergy, especially High Church ones, who reluctantly accept it as a bizarre consequence of the 1707 Act of Union. But Queen Elizabeth II did not find it odd. For six weeks every summer, she attended Sunday worship at Crathie Kirk, a small but slightly forbidding village church near the castle. So did all her predecessors dating back to Queen Victoria, a bust of whom glares at the congregation from the side of the sanctuary. It was actually Victoria’s decision to worship at Crathie, and it was not well received in the Church of England. The truth is that nothing in the Act of Union requires the monarch to attend the Kirk. Victoria did so because she took the very Protestant view that Anglican bishops of the Episcopal church were ‘dissenters’ in Scotland.
So far as we can tell, Queen Elizabeth was not particularly interested in the theological differences between the Churches of England and Scotland.