Even the suspicion that such a network might exist and be interfering with the judicial process clouded the relationship between police, who assemble cases, and the Crown Office (the equivalent of the English Director of Public Prosecutions), which decides whom to prosecute.
The rumours were given substance in January 1990, when Scottish newspaper editors were called to the home of Lord Hope, Lord President of the Court of Session, Scotland's senior judge, to be told, unattributably, that three judges had been questioned about homosexual activities.
The number shocked the legal establishment. All the judges involved were in the Court of Session, the supreme court of Scotland, where there are only 24 judges. One allegation involved two judges entertaining young homosexuals at a cottage in south-west Scotland. Another involved the appearance, briefly, of a judge at a homosexual disco.
Scottish advocates do not work from chambers, but from their homes. Many leading advocates, solicitors and judges live in the New Town area of Edinburgh.
The 11-page leaked report, by a senior detective from Lothian and Borders Police, details facts and speculation surrounding Crown Office decision not to prosecute in some cases and to abandon others. The five cases mentioned in the report are:
A fraud involving a six-figure sum and involving a Scottish- based building firm;
An investigation surrounding embezzlement in a collapsed solicitor's firm, where the two partners involved were homosexual;
A three-year inquiry into an alleged mortgage fraud in which a leading advocate was a suspect;
The withdrawal of 47 of the 57 charges brought in a case concerning claims by a 16-year-old boy who ran away from a children's home. His claims led to an inquiry into a network of homosexuals who used a male prostitute to procure young men for sex. Five of the 10 accused walked free, one went to trial and was found not proven and the remaining four pleaded guilty to reduced charges;
Allegations that a sheriff had been photographed in compromising sexual acts.
Tam Dalyell, Labour MP for Linlithgow, last night confirmed the accuracy of the Edinburgh newspaper's report.
Mr Dalyell said he had written to the Prime Minister on Thursday asking for further investigation of the affair, after Lord Hope had told him he could take the matter no further.
Mr Dalyell said: 'I have no idea who leaked to the Edinburgh Evening News this police report, of which I have had a copy for some time.'
The implications for the constitutional relationship between the police and the Crown Office in the contents of the report, and the fact that they have now become public, were underlined last night by the wording of a statement from Hector Clark, Lothian's Deputy Chief Constable.
Without denying the potentially explosive substance of the document, he took pains to try to distance the force from appearing to criticise the Crown Office.
He said: 'From the police point of view, all allegations or suggestions of criminal activity have been sent to the procurator fiscal. There may be other issues investigated which, in some cases, involve speculation, rumour and some guesswork, and those issues are merely noted.
'On cases submitted to them, the Crown Office decide on whether or not to prosecute and the nature of charges. Occasionally, additional inquiries are ordered by them and undertaken by the police. The Crown may arrange to precognise (to take evidence on oath from) witnesses and others, and the police are often unaware of the total case this process reduces.'
The statement added: 'We are unable, therefore, to comment on decisions made, although the Chief Constable has no lack of confidence in the Crown Office and the judicial process . . .'