Various rights associated with a fair trial are explicitly proclaimed in Article 10 of the Universal Declaration of Human Rights, the Sixth Amendment to the United States Constitution, and Article 6 of the European Convention of Human Rights, as well as numerous other constitutions and declarations throughout the world. There is no binding international law that defines what is not a fair trial; for example, the right to a jury trial and other important procedures vary from nation to nation. 
Definition in international human rights law
The right to fair trial is very helpful in numerous declarations which represent customary international law, such as the Universal Declaration of Human Rights (UDHR).  Though the UDHR enshrines some fair trial rights, such as the presumption of innocence until the accused is proven guilty, in Articles 6, 7, 8 and 11,  the key provision is Article 10 which states that:
"Everyone is entitled in full equality to a fair and public hearing by an independent and impartial tribunal, in the determination of his rights and obligations and of any criminal charge against him."
Some years after the UDHR was adopted, the right to a fair trial was defined in more detail in the International Covenant on Civil and Political Rights (ICCPR). The right to a fair trial is protected in Articles 14 and 16 of the ICCPR which is binding in international law on those states that are party to it.  Article 14(1) establishes the basic right to a fair trial, article 14(2) provides for the presumption of innocence, and article 14(3) sets out a list of minimum fair trial rights in criminal proceedings. Article 14(5) establishes the right of a convicted person to have a higher court review the conviction or sentence, and article 14(7) prohibits double jeopardy.  Article 14(1) states that:
"All persons shall be equal before the courts and tribunals. In the determination of any criminal charge against him, or of his rights and obligations in a suit at law, everyone shall be entitled to a fair and public hearing by a competent, independent and impartial tribunal established by law. The press and the public may be excluded from all or part of a trial for reasons of morals, public order or national security in a democratic society, or when the interest of the private lives of the parties so requires, or to the extent strictly necessary in the opinion of the court in special circumstances where publicity would prejudice the interests of justice; but any judgement rendered in a criminal case or in a suit at law shall be made public except where the interest of juvenile persons otherwise requires or the proceedings concern matrimonial disputes or the guardianship of children." 
Geneva Conventions – International right to a fair trial when no crime is alleged
The Geneva Conventions guarantee combatants the right not to be put on trial for fighting in a war – unless they commit a war crime (a grave breach) or other crime (e.g., captured behind enemy lines out of proper uniforms or insignia while carrying out espionage or sabotage operations). Most held under the Geneva Conventions are not accused of a crime and therefore it would be a war crime under the Geneva Conventions to give them a trial. This protection against getting a trial is fully consistent with human rights law because human rights law prohibits putting people on trial when there is no crime to try them for. The Geneva Conventions however guarantee that anyone charged with a war crime or other crime must get a fair trial.
Definition in regional human rights law
The right to a fair trial is also enshrined in articles 5, 6 and 7 of the European Charter on Human Rights and articles 2 to 4 of the 7th Protocol to the Charter. 
Relationship with other rights
The right to equality before the law is sometimes regarded as part of the right to a fair trial. It is typically guaranteed under a separate article in international human rights instruments. The right entitles individuals to be recognised as subject, not as object, of the law. International human rights law permits no derogation or exceptions to this human right.  Closely related to the right to a fair trial is the prohibition on ex post facto law, or retroactive law, which is enshrined in human rights instrument separately from the right to fair trial and can not be limited by states according to the European Convention on Human Rights and the American Convention on Human Rights. 
Fair trial rights
The right to a fair trial has been defined in numerous regional and international human rights instruments. It is one of the most extensive human rights and all international human rights instruments enshrine it in more than one article.  The right to a fair trial is one of the most litigated human rights and substantial case law that has been established on the interpretation of this human right.  Despite variations in wording and placement of the various fair trial rights, international human rights instrument define the right to a fair trial in broadly the same terms.  The aim of the right is to ensure the proper administration of justice. As a minimum the right to fair trial includes the following fair trial rights in civil and criminal proceedings: 
- the right to be heard by a competent, independent and impartial tribunal
- the right to a public hearing
- the right to be heard within a reasonable time
- the right to counsel
- the right to interpretation 
States may limit the right to a fair trial or derogate from the fair trial rights only under circumstances specified in the human rights instruments. 
In the United States
In the United States the right to a fair trial is sometimes illusory. For example, the United States Supreme Court said in that a prosecutor may threaten a person that he will take or withhold an official act and prosecute that person for crime unless that person disposes or parts with their right to peacefully and orderly petition the courts for a redress of grievances. For example, the Rumery court said when talking about an accused ″the public interest opposing involuntary waiver of constitutional rights is no reason to hold the agreement here invalid.″ Rumery did not receive nor waive their right to a trial during a criminal cause.
In civil proceedings
The European Court of Human Rights and the Inter-American Court of Human Rights have clarified that the right to a fair trial applies to all types of judicial proceedings, whether civil or criminal. According to the European Court of Human Rights, Article 6 of the European Convention on Human Rights and the fair trial rights apply to all civil rights and obligations created under domestic law and therefore to all civil proceedings (see Apeh Uldozotteinek Szovetsege and Others v. Hungary 2000). 
In administrative proceedings
Both the European Court of Human Rights and the Inter-American Court of Human Rights have clarified that the right to a fair trial applies not only to judicial proceedings, but also administrative proceedings. If an individual's right under the law is at stake, the dispute must be determined through a fair process. 
In special proceedings
In Europe special proceeding may also be subject to Article 6 of the European Convention on Human Rights.  In Mills v. the United Kingdom 2001 the European Court of Human Rights held that a court-martial was subject to Article 6 because of the defendants had been accused of what the court considered to be serious crime, assault with a weapon and wounding.
The African Commission on Human and Peoples' Rights (ACHPR) frequently deals with instances where civilians are tried by military tribunals for serious crimes. The ACHPR has held that on the face of it military courts to do not satisfy civilians' right to a fair trial (see Constitutional Rights Project v. Nigeria ). In this respect the ACHPR has reaffirmed the right to counsel as essential in guaranteeing a fair trial. The ACHPR held that individuals have the right to choose their own counsel and that giving the military tribunal the right to veto a counsel violates the right to a fair trial. 
Impeding a fair trial
A fair trial might be impeded by:
- Contempt of court (typically by the media or jurors)
- Witness intimidation
- Non-disclosure of evidence, through malice or through use of state secrets privilege (in the USA) or public-interest immunity (in the UK)
In the Spanish legal justice system the examining magistrate is the head of the investigation of a specific crime and any other matters that may relate to that particular offence. The magistrate can be aided by the judicial and national police and can also, at the request of the prosecution and defence attorney, follow any number of leads regarding the case. The magistrate can also, when deemed appropriate, restrict the access the defence and prosecution have to the primary evidence and case information, which can include allowing witness statements to be introduced without the actual witness having to be in attendance. An extension of this power is the ability for the judge to declare, under special circumstances, the trial wholly or partially confidential.  However, this is only when information and evidence presented during the trial could pose a threat to an individual, a group of individuals or even the general interest of the public. 
In the United Kingdom
Between 1971 and 1975, the right to a fair trial was suspended in Northern Ireland. Suspects were simply imprisoned without trial, and tortured by the British army for information. This power was mostly used against the Catholic minority. The British government supplied deliberately misleading evidence to the European Court of Human Rights when it investigated this issue in 1978.  The Irish government and human rights group Amnesty International requested that the ECHR reconsider the case in December 2014.  Three court cases related to the Northern Ireland conflict that took place in mainland Britain in 1975 and 1976 have been accused of being unfair, resulting in the false imprisonment of the Birmingham Six, Guildford Four and Maguire Seven. These convictions were later overturned, though an investigation into allegations that police officers perverted the course of justice failed to convict anyone of wrongdoing.
The United Kingdom created an act – the Special Immigration Appeals Act in 1997, which then led to the creation of the Special Immigration Appeals Commission (SIAC).  It allowed for secret evidence to be stated in court; however, it provides provisions for the anonymity of the sources and information itself. The judge has the power to clear the courtroom of the public and press, and the appellant if need be, if sensitive information must be relayed. The appellant is provided with a Special Advocate, who is appointed in order to represent their interests, however no contact can be made with the appellant after seeing the secret evidence. SIAC is mostly used for deportation cases, and other cases of public interest. 
Secret evidence has seen increased use in UK courts. Some argue that this undermines the British criminal justice system, as this evidence may not come under proper democratic scrutiny. Secret evidence can now be used in wide range of cases including deportations hearings, control orders proceedings, parole board cases, asset-freezing applications, pre-charge detention hearings in terrorism cases, employment tribunals and planning tribunals. 
Juries and a fair trial
The rationale for a jury was that it offers a check against state power.
Under Article 6 of the ECHR, the right to a fair trial implies that accused and public must be able to understand the verdict. Trials decided by jury, as they do not provide reasons for their decision, therefore do not allow for this.  In Taxquet v Belgium  a violation of article 6(1) was found. The court also implied a right to a reasoned verdict, irrespective of whether that was given by a judge or a jury.
Under ECHR case law, jury decisions can also be problematic in circumstances where juries draw adverse inferences from trial judges' directions in contravention of Article 6(3) (b) and (c). 
EU member states that do not have a jury system or any other form of lay adjudication in criminal matters or have abolished it include: Cyprus, Latvia, Lithuania, Luxembourg, the Netherlands, and Romania. In these countries, criminal courts are composed exclusively of judges.
EU member states with a collaborative jury system which comprises a combination of jurors and judge include Bulgaria, Croatia, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Italy, Norway (in most cases), Poland, Portugal, Serbia, Slovakia, Slovenia, and Sweden. The collaborative system, which can also be employed alongside the traditional jury model, is characterised by the professional judges and the jurors collectively determining all questions of law and fact, the issue of guilt and the sentence.
Within the EU, the traditional jury system exists within Austria, Belgium, Ireland, Malta, Norway (only in serious appeal cases), Spain and the United Kingdom (England, Wales, Scotland and Northern Ireland).
With the expansion of the EU, It is seen as problematic that juries are used, given that their use cannot ensure all the guarantees set out under Article 6, particularly in the ever-expanding landscape and corpus of European law.
Children and the trial process
The issue of children and juvenile engagement with court proceedings and the criminal justice system is a contemporary issue when dealing with the human right of a fair trial. Juveniles need to be competent to stand trial and be able to comprehend the proceedings for their criminal trial to be considered a fair trial. This stands as a contentious issue because many argue that it may never be fair for children to have a role in trial or be involved in criminal justice proceedings due to their age, inability to grasp legal concepts etc.
In discussing children in the legal system, the Netherlands and Sweden provide for an intriguing contrast, which assists in understanding of the different punitive measures applicable. In Sweden, children under the age of 15 are not held accountable for the crimes, which they may have committed. Young people aged between 15 and 18 are generally sentenced to a fine or placed in a social services care agreement by order of the court. This care can often be in combination with fines or additional community service. 
It is a rare occurrence for young people to be sentenced to imprisonment. For the most serious crimes, such as murder and manslaughter, the penalty may be institutionalisation at a specialised youth home. The National Board of Institutional Care is responsible to enforce these sentences. This punishment is for a fixed term, and its focus is on care, treatment and the rehabilitation of young offenders. By contrast, the age of criminal responsibility in the Netherlands is 12. A specialised youth police and courts system was reintroduced in the Netherlands, in order to provide for a specialised task force to deal with youth crime. At the age of 16, an offender who commits crime may be tried in an adult court. The ‘stop and halt’ program is also aimed at punishing young offenders. Younger children under the age of 12 can be ‘stopped’ when they offend, with the main aim at confronting the onset of delinquency. Older children (over the age of 12) can be ‘halted’, with successful completion meaning no criminal record and no prosecution for the young offender in the hope of rehabilitation. 
The main difference between the Netherlands and Sweden in terms of children in court revolves around how the Netherlands tailors its law around its juvenile offence framework, meaning that each case is directly measured against that offender’s individual circumstances. In Sweden, the court system for children is not tailored towards their individual needs, rather the framework of the juvenile court system is based on the adult court system. However, in Sweden, unlike in the Netherlands, the mitigating circumstance of youth applies in order to provide for a young offender’s needs.