The theory that the legislative, executive and judicial powers should be separated is attributed to both French political philosopher Baron de Montesquieu and English judge Sir William Blackstone, although Blackstone only went so far as to state the necessity for some degree of separation of the administration of justice from both parliament and the executive. Despite the theory, historically there was no formal separation of the English judiciary: the Lord Chancellor was a member of cabinet, the presiding officer of the House of Lords and the head of the judiciary, the Law Lords in the House of Lords were the final court of appeal and some serving judges sat in the House of Commons.
