The Working Group is mandated to receive and verify information from a variety of sources, in order to investigate cases of detention imposed arbitrarily, or otherwise inconsistently with the relevant international standards set forth in the Universal Declaration of Human Rights.
The Working Group may send urgent appeals to governments to ascertain the whereabouts and condition of those allegedly detained, issues opinions on the compliance with international law and may also conduct fact-finding visits to countries.
Ensuring a communicative dialogue with Governments and intergovernmental and non-governmental organisations allows the Working Group to achieve success.
[10] The informal nature of the Working Group can strengthen the position of the individual represented, by easing the objective burden of proof on them.
The source must provide sufficiently reliable information that the continuation of deprivation poses significant threat to the psychological or physical wellbeing to the individual.
The Working Group request immediate action to ensure the detained person's right to life, as well as physical and mental integrity are respected.
More generally, the Working Group seeks to encourage broader international understanding of arbitrary detention, and promote universal standards.
[4] The Group formulates deliberations on general issues to assist States in safeguarding against the practice of arbitrary deprivation of liberty.
For example, the Group have developed deliberations on issues relating to house arrest, psychiatric detention, deprivation of liberty subsequent to a conviction and resulting from the use of the internet, on rehabilitation through labour and situations regarding immigrants and asylum seekers.
The opinions of the Working Group are considered authoritative by some prominent international judicial institutions including the European Court of Human Rights.
[13] The features of the Working Group arguably play a role in its success, as it allows it to provide a politically viable alternative to treaty-based human rights enforcement mechanisms.
A further criticism of the Group is that it has taken no steps toward creating a robust follow-up procedure, to apply pressure on states arbitrarily detaining individuals.
Establishing a systematic follow-up procedure could ensure an even greater accountability on governments, acting as a name and shame process to pressure them into action.
[16] On 5 February 2016, the group released a report stating that Assange had been subject to arbitrary detention by the UK and Swedish Governments since 7 December 2010, including his time in prison in Britain and Sweden, on conditional bail, and in the Ecuadorian embassy.
[19] Then-UK Secretary of State for Foreign and Commonwealth Affairs, Philip Hammond, said the claim was "ridiculous" and that the group was "made up of lay people", and called Assange a "fugitive from justice" who "can come out any time he chooses".
[23] Mark Ellis, executive director of the International Bar Association, stated that the finding is "not binding on British law".
[24] United Nations High Commissioner for Human Rights Zeid Ra'ad al Hussein has claimed that the finding is based on international law.
Senior District Judge (Chief Magistrate) Emma Arbuthnot did not find that Mr Assange's stay in the Embassy was "inappropriate, unjust, unpredictable, unreasonable, unnecessary or disproportionate.
"[26][27] In September 2021, shortly after Donziger was sentenced in a New York for petty contempt of court, the group determined that Donzinger's arrest was arbitrary and a violation of international law and called for his release.
The group called on the US government to conduct a thorough investigation of the circumstances of Donziger's prosecution and imprisonment and to "take appropriate measures against those responsible for the violation of his rights.