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A father and son were charged with kidnap after making a "citizen's arrest" on a boy they alleged smashed a window and spat at a customer at their chip shop. But can't anyone make a citizen's arrest?
Arresting a fellow citizen could make you end up in court
The law provides general powers that allow any person to make a citizen's arrest under certain circumstances - including if they witness an arrestable offence. However, there are many legal issues which make it a complex matter with many grey areas.
Chip shop owner Nicholas Tyers, 46, and son Lee, 20, appear to have fallen foul of some of these grey areas after they spotted the 12-year-old suspect in the street and drove him back to their Bridlington shop, a day after the alleged offence, before alerting police.
Mr Tyers said he believed he was "doing his public duty" but then endured "six months of hell" until his case was dismissed by Judge John Dowse at Hull Crown Court.
The judge said the Tyers had acted "reasonably", leaving the Crown Prosecution to defend the prosecution as "being in the public interest".
The case highlights the legal complexity and possible dangers of carrying out a citizen's arrest. The current powers of citizens' arrest, that apply to "any person", are broadly covered by three parts of the law.
• Arrest for an "indictable offence" under the Police and Criminal Evidence Act 1984.
• Arrest of persons committing, or about to commit a Breach of the Peace under common law.
• Use of reasonable force to prevent crime or arrest offenders or persons unlawfully at large under the Criminal Law Act 1967.
Police Community Support Officers (PCSOs) and store detectives rely on these powers for aspects of their jobs.
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In its guidance to PCSOs, the Association of Chief Police Officers details cases which it says clarify a "deliberate policy to ensure that citizens only arrest in the clearest of circumstances".
John O'Connor, former commander of the Flying Squad, explained why citizens' arrests could be unpopular with law enforcers.
"The police don't particularly like citizens' arrests like this because very often the person who's making the arrest is putting themselves at risk," he says.
"They are putting themselves at risk - A of being assaulted by the person they are trying to arrest and secondly they may not necessarily understand what their powers are and they may go too far."
"We have often seen cases that do get prosecuted, where somebody, and usually it is a youngster, is taken from where he's arrested back to a premises where there's some form of interrogation or argy bargy that goes on that could be construed as him being held under duress."
Normal citizens hadn't had the same training as store detectives or Police Community Support Officers to carry out the task, he says.
"If they haven't got the training they run the risk of not doing it correctly," he says.
Mr O'Connor says the "surrounding circumstances" of Mr Tyers' case had made their citizen's arrest "unwise". These included that the suspect was a child and the arrest was made a day after the alleged offence, he says.
'Reasonable' - discuss
Barrister Jodie Dunn says there isn't a form of words people must use when making a citizen's arrest but the person had to be informed they were under arrest "so that they understand what you are doing".
"You're allowed to restrain them and you're allowed to use reasonable force, but the word "reasonable" is something that's used in British law in an awful lot of different statutes and it always causes problems because you have to look at what's reasonable in those circumstances."
Community Support officers use the powers of citizen's arrest
She says that people needed to remember if the arrest was unlawful or it was proved later the suspect had not committed the crime, or the force used to detain them was too great "you could be the one facing charges later on".
Mr O'Connor says it comes down to a "question of balance", adding: "The CPS is trying to send a message that this is not to be undertaken lightly".
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