Not infrequently I hear someone say that they are going to prosecute someone for what happened. Similarly I am amused to read notices saying "Trespassers [or Shoplifters] will be prosecuted." Not necessarily. Presumably it is not quite as eye-catching to say that "Anyone caught trespassing/shoplifting will be reported to the Procurator Fiscal who has an absolute discretion to decide whether or not to prosecute in the public interest."

The flaw in the claim is that private prosecution has no effective role in Scotland. With rare statutory exceptions, all prosecutions in Scotland are commenced and undertaken by the Procurator Fiscal. Even where the exception is available, for example in Customs and Excise cases, such prosecutions are almost invariably by the Fiscal.

The Fiscal acts in the public interest and it is exclusively his right [subject to any directions by the Lord Advocate, whose personal representative he is, and the Law] to decide whether anyone should be prosecuted, on what charge and in which Court. It is not for the victim to say what is, or is not, to happen. "I am not pressing charges" is a meaningless statement from anyone other than the Fiscal.

Private prosecution is not entirely banned. There were two in the last 100 years. It is competent only in, and requires the permission of, the High Court; the view of the Lord Advocate, who has presumably refused to prosecute, carries considerable weight in deciding whether permission should be granted; the intended prosecutor has to show that he personally was a victim of the crime and that the crime is not one against public justice.

People are affronted, and very angry, when they consider that a witness has committed perjury. The perjury may have resulted in an unjust conviction. Clearly a serious crime has been committed here. When perjurers are prosecuted, it is almost invariably on indictment and imprisonment imposed following conviction. There is an obvious victim personally affected by the crime. However private prosecution will not be allowed because perjury is a crime against public justice.

Incidentally the infamous quote of "being economical with the truth" apparently made by a senior civil servant giving evidence on behalf of the government in a trial, stands starkly in contrast with the terms of the oath taken by all witnesses to tell the truth, the whole truth and nothing but the truth. Was I the only person horrified when he was subsequently ennobled by Margaret Thatcher?

Returning to our by now frustrated victim of the perjury, what steps can he take to remedy the wrong? He can always try to persuade the Fiscal to prosecute the perjurer. The problem is that such a crime is no different from any other in that the Fiscal has to prove his case on sufficient evidence and beyond reasonable doubt. The fact that a witness says one thing on one occasion and the opposite on another, does not prove they lied on oath. After all, which statement was the truth? Giving different versions simply makes that witness less reliable. Furthermore for it to be perjury, the false statement has to be deliberately made and material. Witnesses get confused and no-one can be expected to remember every detail precisely. The Fiscal has to prove the false statement was deliberately made. It is hardly surprising that perjury prosecutions are rare.

That leaves the Civil route. Sue the perjurer for damages. As the proof requirements are lower and the defender is obliged to answer, it may be easier to win than a criminal case. Remember OJ Simpson who was found not guilty of the murder and lost his civil case However as in any civil case, he still has to prove his case and, if he fails to win it, faces what may be a substantial bill for costs. Unfortunately even if he wins, that will not affect his criminal conviction and is not a ground of appeal.

On a lighter note, three fathers were boasting about their children. "Deirdre is only 30 but she is such a good Advocate, she is already being talked about as a future judge" said the first. The second responded that his son was not yet 30 but his skills with the knife have marked him out as a great surgeon already. The third thought for a moment and was not going to be outshone by the others. His response? "My son is only 16 but already the police are asking him to help them with their enquiries."