A/HRC/27/47 accordance with article 53 of the Vienna Convention on the Law of Treaties. The concern of the survey has not been with the factual compliance with international law, domestic legislation, the jurisprudence of higher courts or statements by governments. The basic principles and guidelines on remedies and procedures on the right of anyone deprived of his or her liberty to challenge the lawfulness of detention before a court, which the Working Group is drafting at the request of the Human Rights Council, is intended as an instrument for securing and improving such compliance. 20