What is the test for a police officer to be excluded from evidence under the Marquis of Queensberry Rule?

Those remarks are in accord with the views expressed by Mr. Justice Lamer in Rothman v. The Queen (1981), 1981 CanLII 23 (SCC), 59 C.C.C. (2d) 30 at pp. 74-5, 121 D.L.R. (3d) 578 at pp. 621-2, [1981] 1 S.C.R. 640: I hasten to say also that, if the second portion of the rule is not a true discretion, it is even less a blanket discretion given Judges to repudiate through an exclusionary rule any conduct on the part of the authorities a given Judge might consider somewhat unfortunate, distasteful, or inappropriate. There first must be a clear connection between the obtaining of the statement and the conduct; furthermore that conduct must be so shocking as to justify the judicial branch of the criminal justice system in feeling that, short of disassociating itself from such conduct through rejection of the statement, its reputation and, as a result, that of the whole criminal justice system, would be brought into disrepute. The Judge, in determining whether under the circumstances the use of the statement in the proceedings would bring the administration of justice into disrepute, should consider all of the circumstances of the proceedings, the manner in which the statement was obtained, the degree to which there was a breach of social values, the seriousness of the charge, the effect the exclusion would have on the result of the proceedings. It must also be borne in mind that the investigation of crime and the detection of criminals is not a game to be governed by the Marquis of Queensberry Rules. The authorities, in dealing with shrewd and often sophisticated criminals, must sometimes of necessity resort to tricks or other forms of deceit and should not through the rule be hampered in their work. What should be repressed vigorously is conduct on their part that shocks the community. That a police officer pretend to be a lock-up chaplain and hear a suspect's confession is conduct that shocks the community; so is pretending to be the duty legal aid lawyer eliciting in that way incriminating statements from suspects or accused; injecting pentothal into a diabetic suspect pretending it is his daily shot of insulin and using his statement in evidence would also shock the community; but generally speaking, pretending to be a hard drug addict to break a drug ring would not shock the community; nor would, as in this case, pretending to be a truck driver to secure the conviction of a trafficker; in fact, what would shock the community would be preventing the police from resorting to such a trick. It must be remembered that the first part of the rule, the reliability test, will have dealt with most of the situations and that the second part of the rule would come into operation on very rare occasions since such conduct would usually have some effect on the reliability of the statement. Nevertheless, it is in my opinion, all the more important to have a rule that is available to deal with those situations which, thanks to the high standard of conduct of the vast majority of our police officers, will be very few but for that reason all the more deserving of immediate and vigorous rebuke. (Italics mine.)