Locus Standi (âstandingâ?) expresses the obligation on a litigant to show (s)he has an interest in the subject matter of the dispute in legal proceedings.
The rules as to standing vary from jurisdiction to jurisdiction and from issue to issue. The rules may be defined by statute or may be found in the case law.
The parties to a dispute arising from a road traffic accident or a contract will normally have no difficulty showing standing.
The difficulties arise in areas such as planning law, environmental law, or constitutional law.
In The State (Lynch) v Cooney  IR 337 at page 369 Walsh J, stated in the Supreme Court:
The question of whether or not a person has sufficient interest must depend upon the circumstances of each particular case. In each case the question of sufficient interest is a mixed question of fact and law which must be decided upon legal principles but, it should be added, there is a greater importance to be attached to the facts because it is only by examination of the facts that the Court can come to a decision as to whether there is a sufficient interest in the matter to which the application relates.
In planning matters the leading case is Lancefort Ltd. v. An Bord Pleanala (No.2)  2 IR 270. There, the Supreme Court, following an examination of the merits of the applicantâs case against the respondent, declined to accord locus standi to the applicant.
In Ireland there is a broad approach to standing in constitutional law cases, exemplified in Horgan v An Taoiseach  2 ILRM 357, where the court described the Plaintiffâs case on standing thus;
At the outset, counsel on behalf of the plaintiff submits that the plaintiff have (sic) locus standi to seek the relief sought in these proceedings as a citizen of Ireland, relying on the approach adopted by the High Court and Supreme Court in Crotty v. An Taoiseach  I.R. 713, McKenna v. An Taoiseach (No. 2)  I.R. 10 and McGimpsey v. Ireland  I.R. 567.
In Mulcreevy v the Minister for Environment, Heritage and Local Government and Dun Laoghaire-Rathdown County Council  1 IR 72, the Chief Justice said in the Supreme Court:
While the applicant accepts that he has no private interest in these proceedings, it is not suggested that he has brought them for any other reason than to ensure that the national monument is not damaged irreparably, as he claims it would be, by the local authority carrying out the motorway project without the necessary statutory consents, approvals and licenses.
â¦I would, accordingly, agree with the conclusion of the learned trial judge that the applicant had locus standi to institute the present proceedings.
In Mulcreevy, the Defendants were constructing a motorway partially on the site of some archeological remains of importance. Effectively, the courts acknowledge that there will be no challenges to such threats to the fabric of Irelandâs history if the standing of public interest parties is not recognized and consequent protection to the historical residue is secured thereby. (The High Court declined to permit the application for judicial review on the grounds of delay; the Supreme Court reversed in circumstances where he applicant had shown a high probability of success if his application went ahead.)
O’Higgins C.J. said in Cahill v. Sutton  I.R. 269 at p. 276:-.
This Court’s jurisdiction, and that of the High Court, to decide questions concerning the validity of laws passed by the Oireachtas is essential to the preservation and proper functioning of the Constitution itself. Without the exercise of such a jurisdiction, the checks and balances of the Constitution would cease to operate and those rights and liberties which are both the heritage and the mark of free men would be endangered. However, the jurisdiction should be exercised for the purpose for which it was conferred- in protection of the Constitution and of the rights and liberties thereby conferred. Where the person who questions the validity of a law can point to no right of his which has been broken, endangered or threatened by reason of the alleged invalidity, then, if nothing more can be advanced, the Courts should not entertain a question so raised. To do so would be to make of the Courts the happy hunting ground of the busybody and the crank. Worse still, it would result in a jurisdiction which ought to be prized as the citizen’s shield and protection becoming debased and devalued.
There are limits to the Irish broad approach to standing. In Incorporated Law Society of Ireland v Carroll  3 IR 145, the Plaintiff (a solicitorsâ representative body) was denied standing in an application to restrain the Defendant from holding himself out as a solicitor.
In Construction Industry Federation v Dublin City Council  2 ILRM 256,
the Supreme Court refused locus standi to the applicant, remarking
Unlike many of the cases in which parties with no personal or direct interest have been granted locus standi there is no evidence before the Court that, in the absence of the purported challenge by the Appellant, there would have been no other challenger. Indeed the evidence appears to be to the contrary.