Contempt of court is a court ruling which, in the context of a court trial or hearing, deems an individual as holding contempt for the court, its process, and its invested powers. Often stated simply as "in contempt," or a person "held in contempt," it is the highest remedy of a judge to impose sanctions on an individual for acts which excessively or in a wanton manner disrupt the normal process of a court hearing.
A finding of contempt of court may result from a failure to obey a lawful order of a court, showing disrespect for the judge, disruption of the proceedings through poor behavior, or publication of material deemed likely to jeopardize a fair trial. A judge may impose sanctions such as a fine or jail for someone found guilty of contempt of court. Typically judges in common law systems have more extensive power to declare someone in contempt than judges in civil law systems.
In civil cases involving relations between private citizens, the intended victim of the act of contempt is usually the party for whose benefit the ruling was implemented, rather than the court itself.
A person found in contempt of court is called a "contemnor." To prove contempt, the prosecutor or complainant must prove the four elements of contempt. These are (1) existence of a lawful order, (2) the contemnor's knowledge of the order, (3) the contemnor's ability to comply, and (4) the contemnor's failure to comply.

United Kingdom
The Crown Court is a court of record under Supreme Court Act 1981 and accordingly has power to punish for contempt of its own motion. The Divisional Court has stated that this power applies in three circumstances:
Where it is necessary to act quickly the judge (even the trial judge) may act to sentence for contempt.
Where it is not necessary to be so urgent, or where indirect contempt has taken place the Attorney General can intervene and the Crown Prosecution Service will institute criminal proceedings on his behalf before the Divisional Court of the Queen's Bench Division of the High Court of Justice of England and Wales (Criminal Division).
Magistrates' Courts are not courts of record, but nonetheless have powers granted under the Contempt of Court Act 1981. They may detain any person who insults the court or otherwise disrupts its proceedings until the end of the sitting. Upon the contempt being either admitted or proved the court may imprison the offender for a maximum of one month, fine them up to GB£2500, or do both.
It is contempt of court to bring an audio recording device or picture-taking device of any sort into an English court without the consent of the court.
It is not contempt of court (under section 10 of the Act) for a journalist to refuse to disclose his sources, unless the court has considered the evidence available and determined that the information is "necessary in the interests of justice or national security or for the prevention of disorder or crime."

Contempt "in the face of the court" (not to be taken literally; the judge does not need to see it, provided it took place within the court precincts or relates to a case currently before that court);
Disobedience of a court order; and
Breaches of undertakings to the court. Criminal contempt of court
Under the Contempt of Court Act 1981 it is criminal contempt of court to publish anything which creates a real risk that the course of justice in proceedings may be seriously impaired. It only applies where proceedings are active, and the Attorney-General has issued guidance as to when he believes this to be the case, and there is also statutory guidance. The clause prevents the newspapers and media from publishing material that is too extreme or sensationalist about a criminal case until the trial is over and the jury has given its verdict.
Section 2 of the Act limits the common law presumption that conduct may be treated as contempt regardless of intention: now only cases where there is a substantial risk of serious prejudice to a trial are affected.

Strict liability contempt
In civil proceedings there are two main ways in which contempt is committed:

Failure to attend at court despite a subpoena requiring attendance. In respect of the High Court, historically a writ of latitat would have been issued, but now a bench warrant is issued, authorizing the tipstaff to arrange for the arrest of the individual, and imprisonment until the date and time the court appoints to next sit. In practice a groveling letter of apology to the court is sufficient to ward off this possibility, and in any event the warrant is generally 'backed for bail' i.e. bail will be granted once the arrest has been made and a location where the person can be found in future established.
Failure to comply with a court order. A copy of the order, with a "penal notice" - i.e. notice informing the recipient that if they do not comply they are subject to imprisonment - is served on the person concerned. If, after that, they breach the order, proceedings can be started and in theory the person involved can be sent to prison. In practice this rarely happens as the cost on the claiming of bringing these proceedings is significant and in practice imprisonment is rarely ordered as an apology or fine are usually considered appropriate.