A Community Protection Notice (or “CPN”) can be issued by a police officer or by a local authority if they are satisfied that the person on whom the notice is issued has engaged in unreasonable conduct, which is having a persistent detrimental effect on the quality of life of those in the locality. A CPN can require a person to stop doing something, to do something, or to take reasonable steps to achieve some particular result. CPNs can only be issued to people aged 16+.
Perhaps the most significant difference between CPNs and most of the other civil orders which are available to the police (or other authorities), is that CPNs can be issued and can take full effect without a court considering them. If the police determine on reasonable grounds that relevant conduct is taking place, then they can issue a notice without reference to anyone else.
The person to whom the CPN is issued does have to have been given a warning first, which must specify that a CPN is being considered, and they must be given enough time to deal with the matter before a CPN is actually issued.
If a CPN is issued, though, the person who receives it does have a right of appeal. This is the way by which a CPN can be brought before an independent court, which can then scrutinise whether the notice was really appropriate and can decide to quash the notice (so that it ceases to exist), or modify it (which might involve changing some of the terms, if they are unreasonable; or changing any time periods in it). Of course the court might also dismiss the appeal, if the original CPN is found to have been properly issued and proportionate, in which case it will continue in force.
If there’s no appeal, and a CPN remains in force, then it must be obeyed even if the terms seem harsh or unreasonable. Breach of a CPN is a criminal offence, and a defendant who is charged with a breach cannot, at their trial, argue that the original CPN is invalid or should not have been made. Any challenge of that kind must be made by way of an appeal.
If a CPN is issued against you, and you disagree with the terms, it is therefore important to appeal against it, not to wait until you get charged with a breach (by which time it would be too late). It should be noted, too, that appeals must be brought quickly – within 21 days of the notice being issued. Information about how to appeal should be provided to you when the CPN is issued.
If you want to challenge a CPN but that 21-day period has expired, there is still one option open to you. The High Court determined in Stannard v CPS  EWHC 84 (Admin) that the original act should be read as if it included a power for the police force or local authority who made the original CPN to vary or withdraw the order. It is therefore possible to write to them, asking for a reconsideration. If they refuse, and if the refusal decision is unreasonable, then it may be possible for a court to judicially review that refusal.
However, this doesn’t mean that one can just ignore the 21-day time limit. For one thing, judicial review is likely to be more expensive than a statutory appeal, and the tests applied by the court make it harder to overturn a CPN by judicial review. The reasons for this, and the case law which governs the way judicial review decisions are made, are complex. If you find yourself in the position of challenging a CPN by judicial review, ask your legal representatives to explain the criteria the court will apply. The key point, however, is that challenging a CPN by appeal is likely to be easier and cheaper.
If you are charged with breach of a CPN, then the proceedings will be similar to those on any other criminal charge. If you plead not guilty, a trial will follow, where the main possible defences are either that you did not breach the notice (because the facts which the prosecution are alleging either are not true, or if they are true, wouldn’t breach the terms of the notice); or else that although you did breach the notice, you had done all that you reasonably could to comply, or you had some other reasonable excuse for failing to comply.
Reasonable excuses might, for example, cover a genuine emergency situation, or a reasonable misunderstanding about what the order mean. But as with any trial, much will depend on the particular facts of the case, and on the strength of the evidence on both sides.
If convicted, the maximum sentence is a fine.