The Prime Minister can no longer pass on the nominations for Church of England bishops to the Queen now that he is technically Catholic.
A quirk of English law means that now Boris Johnson has been married in a Catholic church and left Anglicanism behind, he can no longer 'advise' the Queen on the nominations for Bishops, who officially approves them.
This has been purely symbolic for many years but if Mr Johnson were to take a sudden interest in the next nomination and tell the monarch his thoughts, he would be guilty of: "a high misdemeanor, and disabled for ever from holding any office, civil or military, under the Crown".
The Times newspaper reports that this comes from the Roman Catholic Relief Act of 1829, which states that no "person professing the Roman Catholic religion" can advise the King or Queen on the appointments.
Robert Buckland, the Lord Chancellor, is likely to take on the role to avoid any such misdemeanor. The Prime Minister was baptised Catholic as an infant but turned to the Church of England later and got married as an Anglican. His recent wedding though was Catholic and commentators suspect his former marriages were not recognised by the Catholic Church.
Upcoming vacancies include the Bishop of Portsmouth and the Bishop of Salisbury.
The decision-making process includes a group of senior clergy and lay people from the correct diocese and members of the Church of England's General Synod, who make up the Crown Nominations Committee.
The Commission holds interviews and identifies two suitable candidates whose names are submitted in order of preference to, now most likely, Robert Buckland. By convention, he will submit the first-named person to the Queen for approval.