In days gone by, important messages were carried between countries which might have been at war. For obvious reasons, killing the messenger could prevent the message from getting to the right people. So, official messengers (‘ambassadors’) became protected.
This developed into the immunity that modern day diplomats, ambassadors, and certain of their staff members enjoy. By international convention, they cannot be prosecuted for criminal deeds.
The party, and the attorney involved, and the court officials who issue or execute any legal process against a person who enjoys diplomatic immunity are all guilty of an offence.1
Under the Diplomatic Immunities and Privileges Act 2001, it is also a crime if, by committing any other offence (e.g. house breaking), someone’s diplomatic immunity, or the diplomatic inviolability of his property or premises, is infringed.2