Court for possible revision. The Constitution established it as a mechanism of last recourse, when the individual has no other means of legal defence, except when it is used as a transitional mechanism to avoid irreparable harm, but it has become one of the most widely used rights protection mechanism in Colombia, likely because it guarantees speedy resolution - within 10 days, according to Article 86. The acción de tutela is used to ensure the immediate protection of fundamental rights, but the Constitutional Court has ruled that "the fundamental character of a right can only be determined in each (individual) case", which means that the rights protected are not limited to those listed in Chapter I of the second title and requiring each judge to analyse each case to determine if it can be protected by an acción de tutela. Decree 2591 of 1991 regulates the acción de tutela. One of the aspects which makes it so popular with citizens is its simplicity and informality - any natural or juridical person may file an application which requires the action or omission which motivated it, the right considered violated or threatened, the name of the public authority responsible for the grievance and the description of other relevant circumstances, along with the name and residence of the applicant. It is not required to cite the specific constitutional rule infringed, and the application may be made through any written form of communication, with a possibility for minors and the illiterate to apply orally. In cases where the request concerns an authority, the judge's decision shall ensure to the aggrieved the full enjoyment of their right and return to the state prior to the violation (if possible). In cases where the request concerns the denial of an act or omission, the judge shall order that the adequate action be taken within 48 hours. Finally, in cases of a conduct, threat or behaviour, the ruling shall order its immediate cessation and prevent any new threat. A 2013 poll of 5,866 people showed that the acción de tutela was the most well-known judicial mechanism, with 83.7% of respondents being familiar with it, compared to between 20 and 25% of respondents who were familiar with the four other rights-protection mechanisms. Furthermore, the study reported that 65% had a favourable opinion of the mechanism against only 11% who viewed it unfavourably. On the occasion of the 20th anniversary