The United Kingdom is under a monarchy and the queen heads the monarch and most of the countries have the queen on their money.
The queen of England Queen Elizabeth II is the only person in the world who enjoys both diplomatic and sovereign immunity and thus cannot be arrested and prosecuted by any law. no matter where.
The sovereign immunity in some way means that the person is above above the law. So the queen can actually commit any crime and still go free. Infact there can never be any arrest in the presence of the queen without her consent so she cannot be arrested because that means her presence will be available there.
The Queen is considered the “fount of justice” for all her subjects, the ability to administer it is doled out to judges across Britain- all of whom are granted the post-nominal of the Queen’s Counsel as a nod to their position as an extension of the Queen’s will
The court also dispense their duties as a result of Her Majesty the queen and so being prosecuted would mean she has to prosecute herself
The Queen cannot in anyway be forced to testify in open court or even be interviewed by the police and thus can’t be arrested.
All the prisoners are also under the queens mercy and even the police who carry out their duties do that as a duty to the queen and even when they make their oath when being recruited to service, they always make those vows in the name of the queen.
Queen Elizabeth II is the current Queen of England and one of the most powerful people in the world and so she is the one who enjoys all the privileges.