revision preference src: Griffith said the Act of Union of Great Britain and Ireland in 1800 was illegal and that there should therefore be one government for Great Britain and another for Ireland. <SEP> tgt: In his writings, Griffith declared that the Act of Union of Great Britain and Ireland in 1800 was illegal and that, consequently, the Anglo-Irish dual monarchy that existed under Grattan's Parliament and the so-called " Constitution of 1782 " were still in effect.