the decision and order that the authority fulfil the expectation. A decision is invalidated by the issuance of a quashing order (also known as certiorari), one of the more common prerogative orders, and often results in the issue returning to the original body to be reconsidered afresh. For example, in Ng Yuen Shiu, a representation was made by the Director of Immigration that each illegal entrant to Hong Kong from Macau, of whom the applicant was one, would be interviewed with each case treated on its merits before a decision was made whether to deport the entrant. However, the applicant was not given an opportunity to make any representations. The Director's failure to provide the applicant with this chance was deemed a sufficient ground for quashing the decision. The Court of Appeal of Hong Kong had ordered a prohibition restraining the removal orders from being executed. However, the Privy Council decided that a prohibition was excessive and issued a certiorari instead. It noted that the latter order did not prevent the Director from making a fresh removal order following a fair inquiry at which the applicant had been given an opportunity to explain why he should not be deported. A quashing order may also be used to protect a substantive legitimate expectation. It sets aside the decision that frustrates the promise made by a public authority to an applicant, thus binding the authority to fulfil its representation. In Ex parte Coughlan, the Court of Appeal of England and Wales held that the applicant had a substantive legitimate expectation for the facility at which she was living to be kept open for the rest of her life, which the health authority was not allowed to frustrate. It therefore upheld the High Court's decision to issue a quashing order to prevent the authority from closing the facility, effectively ensuring that the facility was kept running for the benefit of its residents. To direct a public body fulfil a legitimate expectation, the court issues a mandatory order (also known as a mandamus). This is a prerogative order which commands a public body to perform a public duty, and is often used to compel public bodies to exercise the powers given to them. Reconsideration of decision In R (Bibi) v Newham London Borough Council (2001), instead of ordering that the public authority fulfil a legitimate expectation that had been breached, the Court of Appeal