In legal terms, an Act of Indemnity is a statute passed to protect people who have committed some illegal act which would otherwise cause them to be subjected to legal penalties.
International treaties may contain articles that bind states to abide by similar terms which may involve the parties to the treaty passing domestic legislation to implement the indemnity laid out in the treaty.
The United Kingdom has three legal jurisdictions.
Those acts passed during the Interregnum (1649–1660) were themselves rendered null and void with the Restoration of the monarchy in England, Scotland and Ireland in 1660.