The Staggers 5 January 2011 The conviction of Michael Thompson Does warning other drivers about speed cameras constitute obstructing a police officer? Sign UpGet the New Statesman\'s Morning Call email. Sign-up One day last July, Michael Thompson was driving in his car in Grimsby. He noticed a mobile speed camera. He also saw that many oncoming cars seemed to be speeding. He flashed those cars to warn them to slow down. It is not known whether any of the cars did slow down but, if so, the road was presumably safer for them reducing their speed and the public interest in drivers staying within the speed limit was achieved. Indeed, he later said that he was trying to warn motorists to prevent them from braking dangerously when they saw the speed trap. However, Mr Thompson was not thanked by the police for any of this. Instead, according to the Daily Telegraph report, he was pulled over. What happened next is not clear. It appears Mr Thompson made the mistake of challenging the police's actions. If so, it seems such petulance had a predictable response from officers who are used to exercising coercive power without any question or accountability. The Daily Telegraph report states that he was threatened – ludicrously – with "perverting the course of justice". If this was the case, it would be a good example of a police officer selfishly invoking the law without actually understanding it. And it would not be the first time. In any case, the officers did not appear to take well to being challenged. The report states that one of the officers then told Mr Thompson: "I was going to let you off with a caution – but I'm not now." If this was said in this circumstance, then it suggests a deplorable and illiberal exercise of discretion by the police officer. Mr Thompson is reported as stating that the officer was "a Rambo character", acting like "Judge Dredd" in using the law against him unnecessarily. It appears that Mr Thompson is suggesting that the police officer was being arbitrary and self-serving in the exercise of his or her powers. We do not know whether this was actually the case. Nonetheless, the outcome of this encounter was rather unfortunate for Mr Thompson. He was charged, not with perverting the course of justice, but with wilfully obstructing a police officer in the course of their duties. This is another criminal offence that police officers resort to when they do not get their way. According to Mr Thompson's account, it appears that the charge was made just because he dared to challenge the officers who pulled him over. However, we do not know whether this is what happened: it could just be his word against the police officers'. But there is perhaps a more fundamental issue in all this, where there does not seem to be any dispute about the facts. How can warning other motorists to reduce their speed be a criminal offence? The "course of duties" which is being supposedly "obstructed" is not the same as the mere convenience of police officers with their speed trap. Mr Thompson did not disable the speed trap, or stand in front of it. Nothing whatsoever stopped the police officers from detecting any speeding motorists at whom they pointed their mobile speed camera. It seemed Mr Thompson simply warned others to regulate their future behaviour so as to eliminate their exposure to criminal liability. If this constitutes "wilfully obstructing a police officer in the course of their duties" then it is what thousands of criminal lawyers do every day for their clients. It is what parents do for their children. It is what shopkeepers do with their signs against shoplifting. Indeed, it is what even police officers often do in the communities they serve. Preventing police officers from seeking to impose as much criminal liability as they possibly can is not the same as "wilfully obstructing a police officer in the course of their duties". Police officers' ability to arrest and charge is not an end in itself, but just one means of serving the wider interests of justice and the public. The criminal justice system does not exist solely for the satisfaction of a police officer wanting to coerce another human being. In the end, poor Mr Thompson was fined £175 (and ordered to pay £250 costs and a £15 victim surcharge) after a half-day hearing last week at Grimsby Magistrates' Court. The full CPS statement for this seemingly illiberal prosecution is: It was the Crown Prosecution Service's case that Michael Thompson flashed the lights of his car to warn other drivers of a speed trap ahead. In doing so, he was obstructing a police officer in the execution of their duty, which is a criminal offence contrary to the Police Act 1996, sect 89 (2). The CPS was satisfied that there was sufficient evidence and it was in the public interest to prosecute the defendant with this offence. After hearing the prosecution's case and Michael Thompson's defence, magistrates at Grimsby Magistrates' Court found the case against him proved. They decided that he knew his action would cause vehicles to slow down and cause other motorists to avoid the speed trap and prosecution. They fined him £175 and ordered him to pay prosecution costs of £250. The CPS press office also pointed me to the Highway Code, which contains the following: Flashing headlights. Only flash your headlights to let other road users know that you are there. Do not flash your headlights to convey any other message or intimidate other road users. However, a breach of the Highway Code is not itself a criminal offence. It can act as evidence of a breach of a substantive motoring offence, such as dangerous driving, but to rely on it in this case seems rather desperate. In fact, a lot about this case as it is reported looks rather desperate. But sadly there is nothing surprising. And so it does seem Thompson now has a criminal conviction because he encouraged others to stay within the law. David Allen Green is a lawyer and writer. He is legal correspondent of the New Statesman. › Facebook fact, Facebook fiction David Allen Green is former legal correspondent at the New Statesman. Subscribe For daily analysis & more political coverage from Westminster and beyond subscribe for just £1 per month!