"For there to be an obstruction of a police constable in the execution of his duty, by the giving of a warning of the presence of a speed trap, is it necessary for the prosecution to prove that those warned either were themselves exceeding the speed limit or were likely to do so at the location of the speed trap?"
"However we held that the persons at whom the hand signals were directed had to be persons who were either actually driving in excess of the speed limit or were likely so to drive at that place and time, and in respect of whom the warning could operate to prevent or obstruct the police in the performance of their duty to detect speeding motorists. Unless there was evidence that there were drivers who were driving in excess of the speed limit or who were likely to do so, there was no obstruction of the police. Here is was accepted that there was no evidence that anybody acted in response to the warning and nobody was detected speeding. Having seen the video we concluded that nobody was speeding. We likened the situation to that which would exist if there had been no other traffic in the vicinity of the [respondent]. Even if he had been trying to warn other motorists there was no offence known to the criminal law of attempting to obstruct the police in the execution of their duty. We distinguished the case of Green v Moore in which, but for the tip off, the police would have detected after hours drinking."
"Bastable v Little is the earliest in the relevant line of cases. It has elements which seem idiosyncratic today. Thus Lord Alverstone CJ said (at 62): 'Suppose a party of men are engaged in the offence of night poaching, and a person passing near warns them that the police are coming, I think it is clear that that could not be held to be an offence within this section. We must not allow ourselves to be warped by any prejudice against motor cars, and so to strain the law against them.' The offence charged was obstructing constables in the execution of their duty as such constables, contrary tos 2 of the Prevention of Crimes Amendment Act 1885 . The police had set up a series of speed traps in London Road, Croydon. Mr Little occupied himself giving warning signals to drivers approaching the traps, thus ensuring that they did not exceed the speed limit. The ratio of the decision is without doubt that there was no evidence that the drivers were exceeding the speed limit at the time when they received Mr Little's signals, although all slowed down. Darling J made this point and added (at page 63): 'In my opinion it is quite easy to distinguish the cases where a warning is given with the object of preventing the commission of a crime from the cases in which the crime is being committed and the warning is given in order that the commission of the crime should be suspended while there is danger of detection, with the intention that the commission of the crime should be re-commenced as soon as the danger of detection is past. In Betts v Stevens the facts were indistinguishable from those in Bastable v Little, save that (a) the cars were exceeding the speed limit of 20 mph when they received the warning which was given by an Automobile Association patrolman, and (b) police officers were observing the cars at the place where the warning was given and the speed trap was intended to provide confirmatory evidence of their opinion that the speed limit had been exceeded. The patrolman was convicted. The court distinguished Bastable v Little on the ground that, contrary to the position in Bastable's case, the motorists were exceeding the speed limit before they entered the measured distance and that the action of the patrolman prevented the police from obtaining confirmatory evidence by timings over that distance. Both Darling and Bucknill JJ, the former expressly and the latter impliedly, stated that the gist of the offence lay in the intention with which the acts complained of were done. If the intention was simply to prevent the commission of crime, no offence was committed. It was otherwise if the intention was to prevent the commission of crime only at a time when there was a danger of detection."
"If Bastable v Little has never yet been criticised, this is a situation which is capable of being remedied. It seems to us to be a very curious decision based on a highly eccentric view of the facts. The decision seems to have proceeded on the basis that prior to the warning the motorists concerned had not exceeded the speed limit and that the warning was intended to discourage them from ever so doing. If that were indeed the position, we would agree that no offence was committed. Far from obstructing the police in the execution of their duty, Mr Little would have been assisting them in one of their most important duties, namely, crime prevention. But a more realistic view of the facts is that the warning was based on a lively anticipation that even if the motorists were not then exceeding the speed limit, they were likely to do so over the measured distance and the warning was intended to discourage them from doing so until after they had passed out of the area of the police trap. However, the court never considered that hypothesis. We cannot see any distinction between a warning given in order that the commission of a crime may be suspended whilst there is danger of detection, which is an offence (see Betts v Stevens) and one which is given in order that the commission of a crime may be postponed until after the danger of detection has passed. We are, of course, bound by Bastable v Little and it must be left to others to consider overruling it. However, it is an authority which, in our judgment, should be strictly confined to the facts as the court found them."
"In my opinion a man who, finding that a car is breaking the law, warns the driver, so that the speed of the car is slackened, and the police are thereby prevented from ascertaining the speed and so are prevented from obtaining the only evidence upon which, according to our experience, Courts will act with confidence, is obstructing the police in the execution of their duty."
"The appellant in effect advised the drivers of those cars which were proceeding at an unlawful speed not to go on committing an unlawful act. If that advice were given simply with a view to prevent the continuance of the unlawful act and procure observance of the law, I should say that there would not be an obstruction of the police in the execution of their duty of collecting evidence beyond the point at which the appellant intervened. The gist of the offence to my mind lies in the intention with which the thing is done. In my judgment in Bastable v Little I used these words: 'In my opinion it is quite easy to distinguish the cases where a warning is given with the object of preventing the commission of a crime from the cases in which the crime is being committed and the warning is given in order that the commission of the crime may be suspended while there is danger of detection.' I desire to repeat those words."