The recent conviction and sentence of Chief James Ibori former Governor of the State of Delta (1999 – 2007) to 13 years imprisonment on 17 April 2012 by Southwark Crown Court presents a unique feature in changing hitherto legal principles of res judicata on finality of proceedings, stare decisis on legal precedent and the legal effect in Nigeria of a conviction and sentence imposed by a foreign court. The outcome of R v. Ibori has a significant impact on the decision of the Supreme Court (Nigeria) in 2005 of the case of Engineer Goodnews Agbi, Anthony Alabi and Chief Audu Ogbeh & ors, a case in which Chief Ibori was one of the parties as one of the defendants/respondents). This paper provides an analysis of the issues in respect of the two cases involving Chief Ibori based on previous cases decided by the Supreme Court, the House of Lords as well as substantive and procedural law in Nigeria.