Similarly, the monarch is totally immune from criminal prosecution and may only be sued with her permission (this is known as sovereign immunity). The monarch, by law, is not required to pay income tax, but Queen Elizabeth II has voluntarily paid it since 1993, and also pays local rates voluntarily. However, the monarchy also receives a substantial grant from the government, the Sovereign Support Grant, and Queen Elizabeth II's inheritance from her mother, Queen Elizabeth The Queen Mother, was exempt from inheritance tax.