WATCH: Shocking moment two civilian security guards ‘slam dunk’ 15-year-old black boy to the ground

This is the shocking moment a black teenager was forcibly detained by private security guards at a Sussex supermarket. 

Footage shows the two men hold the teenager on the ground while they handcuff him before the arrival of police. 

The incident happened at the Chichester branch of Superdrug. 

Sussex Police confirmed they have launched an investigation following the incident. 

One of the boy’s friends called his mother Kirsty Buchanan who later released footage of the incident on Twitter. 

Sussex Police said they arrested two boys aged 15 and 16 on suspicion of assault at the Chichester branch of Superdrug

Ms Buchanan told The Mirror the security guards were aggressive towards her son and his friends. 

‘What I have been told is the ranger pushed him and my son pushed back.

‘He was then slam dunked to the floor and 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.’

The woman said she did not hear from her son for an hour and a half as he was being held at Worthing Police Station.

She added: ‘The rangers that threw him to the ground have gone home to have tea.’

Ms Buchanan, who previously worked as a special advisor at 10 Downing Street and the Ministry of Justice, said her son has regularly experienced racist incidents and has been stopped and searched many times.  

Sussex Police told MailOnline: ‘We are aware of a video circulating on social media of a teenager being detained by civilian security staff in Chichester this afternoon (22 March).

‘Police were called to the store in East Street shortly after 3.30pm to reports of a group of teenagers involved in an altercation.

The boy’s mother, Kirsty Buchanan said the security guards ‘dunked’ her son to the ground before restraining his arms with plastic handcuffs

A spokesperson for Superdrug confirmed an incident happened in their Chichester store, pictured. They said a female staff member was allegedly assaulted

‘A shopworker also reported being assaulted.

‘Officers attended the scene and three teenagers had been detained by civilian security staff.

‘A 15-year-old boy from Worthing and a 16-year-old boy from Chichester were arrested by police on suspicion of assault.

‘They remain in police custody pending urgent enquiries, supported by appropriate adults.

‘Enquiries are ongoing to establish the full circumstances of what happened.’

A spokesperson for Superdrug told MailOnline: ‘An incident occurred today in our Chichester store between Chichester BID Rangers and a group of young males they were monitoring. 

‘Unfortunately, female staff were also assaulted. This is now a police matter, and we are offering our full assistance to Sussex Police. 

‘Our priority is always to keep our colleagues and customers safe, we have a zero-tolerance policy when it comes to violence and aggression. The store remains closed due to damage caused.’