Police have warned that any handcuffing by civilians must be justified after two rangers sat on a black teenager reportedly buying shampoo at Superdrug.
Distressing footage of the incident involving a 15-year-old being restrained by security staff at the store in Chichester, West Sussex, has sparked widespread controversy on social media.
It shows the civilian rangers - employed by the Chichester Business Improvement District (BID) scheme - putting plastic handcuffs on the teenager and kneeling across his legs.
The video raised concerns amongst members of the public about security workers "policing" business premises and being able to use restraints in a citizen's arrest.
Sussex Police has since clarified that there is no law in the UK which prevents civilians carrying handcuffs.
Brighton beach evacuated as bomb squad blow up 'World War 2 shell' near pierBut it added: "Anyone who does carry handcuffs should be aware that their use could constitute a crime, unless they can show that using them was reasonable and proportionate in the circumstances."
Meanwhile, the Security Industry Authority (SIA) regulator said it "neither endorses nor declines handcuff use", and that it will investigate any licence holders "who fail to comply with its licencing conditions".
Pranav Bhanot, Litigation Partner at WYN Legal, has now claimed that the teenager could bring a false imprisonment claim against the rangers if there were no reasonable grounds for the citizen's arrest.
After viewing the footage, he told the Mirror: "In my view using handcuffs can go towards evidence that disproportionate force was used. It seems on the face of it excessive."
Police officers were called to the shop shortly after 3.30pm yesterday to reports that a group of teenagers had become involved in an altercation and a shop worker also allegedly being assaulted.
The force said that two children arrested in connection with the incident have since been released on bail.
It added in a statement: "On arrival, officers discovered a 15-year-old boy from Worthing had been detained in handcuffs by privately employed civilian security staff. He was arrested on suspicion of assault."
The teenager's mum, Kirsty Buchanan, had claimed that "aggressive" rangers confronted her son while he was shopping for shampoo and "slam-dunked" him to the ground before handcuffing him.
She told the Mirror: "They (the rangers) started to get aggressive towards them and one of them got into my son's personal space and he asked, 'can you get out of my face'.
"What I have been told is the ranger pushed him and my son pushed back."
Man, 24, in hospital after assault during football match that had to be stoppedShe claimed: "He was then slam-dunked to the floor and (they) sat on top of him as you see in the video and they put plastic handcuffs on him - the police then arrived and arrested my son."
Lawyer Mr Bhanot has since commented on whether the rangers were justified in using handcuffs on the teenager.
He said: "The teenager could bring a false imprisonment claim if there were no reasonable grounds for the citizen's arrest.
"In order to be a security guard you need an SIA licence and various qualifications.
"It does raise wider issues about the role that these rangers are playing in our shopping districts."
Police said a "full and thorough investigation is ongoing to establish the exact circumstances of what happened", with officers reviewing footage and taking witness statements.
It continued: "Sussex Police has been in contact with the 15-year-old’s mother and contact will be maintained as the investigation continues."
The force said a second teenager - a 16-year-old boy from Chichester - was arrested on suspicion of assault, possession of cannabis, and using threatening, abusive or insulting words or behaviour to cause harassment, alarm or distress.
Superdrug clarified that the two rangers were not employed by the chain, and that it is assisting police with their investigation.
It said in a statement: "The Chichester BID rangers are not employed by Superdrug. The incident which unfortunately occurred in our Chichester store was between Chichester BID Rangers and a group of young males they had been monitoring.
"We cannot provide any further details at this stage, as this is now a police matter, and we are offering our full assistance to Sussex Police.
"We would like to reassure customers and members of the public that our priority is always to keep our colleagues and customers safe, and we have a zero-tolerance policy when it comes to violence and aggression in our stores."
Chichester BID was approached over its use of plastic handcuffs.
Its website states that it will "deliver a team of Rangers, in partnership with Chichester City Council, that are the eyes and ears on the street and a reassuring presence for those in the front line of petty crime."
It released a statement saying: "Chichester BID is aware of an incident that occurred on 22 March at the Superdrug store on East Street, involving a group of young people and two Rangers.
"Together with Blayde Security, who provide our security services, we are cooperating fully with Sussex Police, who are investigating the matter. We are taking this very seriously.
"We want to reassure traders, residents and visitors to Chichester city centre that we are committed to providing a safe and secure environment for all."
Blayde Security said that one of its officers suffered a head injury in the incident - however, Ms Buchanan claimed that this happened when her son "threw his head back while being pinned to the floor".
The security firm said in a statement: "We are aware of an incident involving our Chichester BID Security Rangers whilst monitoring a group of people in the Superdrug store, East Street.
"This is now a police matter and, along with Chichester BID, we are offering our full assistance to Sussex Police with their investigations.
"Our priority is always to keep members of the public, our staff and our partners safe and we have a zero-tolerance policy when it comes to violence and aggression.
"One of our security officers was injured during this incident and has been released from hospital having suffered significant head trauma and he is now at home with his family having received excellent care. A shopworker was also reported being assaulted.
"We have no further comment to make at this stage as this is a live police investigation."
Meanwhile, the SIA regulator said it is supporting police with their investigation.
It added: "Should a licence-holder do anything that means they fail to comply with our licensing conditions, or they do not live up to the standards of behaviour we require, we will investigate the matter.
"We neither endorse nor decline handcuff use. There is no law in the UK that prevents civilians carrying handcuffs. Licensed security operatives have no legal powers over and above other civilians. Anyone who does carry handcuffs should be aware that their use could constitute a crime, unless they can show that using them was reasonable and proportionate in the circumstances.
"We licence individuals to operate within specified sectors according to the Private Security Industry Act. We do not licence businesses.
"We have a statutory responsibility to recognise those businesses wanting to meet increased standards. We do this by managing the voluntary Approved Contractor Scheme (ACS)."
Anyone who witnessed the incident, the events leading up to it or has any relevant footage is urged to contact police online or via 101, quoting Operation Ashridge.