Body-worn video of a woman's "degrading" arrest, which police falsely told a court did not exist, has been shared exclusively with the BBC.

It shows officers in Northamptonshire throw metal spikes in front of Nadine Buzzard-Quashie's car and force her to the ground after responding to a concern for her welfare, whereupon she says her face was pushed into stinging nettles.

The Chief Constable of Northamptonshire, Ivan Balhatchet, was found guilty of contempt of court in November and fined £50,000 for failing to release the body-worn videos to her.

Buzzard-Quashie claims that after her arrest, officers removed CCTV she was carrying of her detention by the Metropolitan Police six months earlier, which included highly intrusive footage of her using a custody toilet.

Both forces declined to comment due to ongoing damages claims for more than £3m, though in its civil defence, Northamptonshire Police insisted the use of force was lawful.

"I don't do well with injustice," says Buzzard-Quashie, 43, from west London, who is the founder of a corporate gifting company.

This is the first time she has spoken publicly about what she calls her "David and Goliath battle".

Her complex story raises serious questions about the police's handling of people's video data.

On 13 March 2021, Buzzard-Quashie was arrested at her home in Ealing, west London, on suspicion of sending malicious communications after posting on Instagram some racist messages she had received from former acquaintances.

She was released after spending 17 hours in custody at Hammersmith police station and the case against her was eventually dropped.

Buzzard-Quashie promptly lodged a formal request to Scotland Yard to release the CCTV of her detention.

When it arrived on 24 August on DVD, she found the Met had, without her knowledge, retained and downloaded unpixelated footage of her using the toilet in her cell.

The BBC has confirmed the existence of this footage, which is described by her lawyers, Bindmans, as "grossly intrusive" and shows "a graphic view of her genitalia".

Buzzard-Quashie reported what she had seen to both London's Mayor, Sir Sadiq Khan, and the then commissioner of the Met Police, Dame Cressida Dick.

But the discovery, she says, brought her close to having a mental health crisis and, on 2 September 2021, she got into her car and left home.

"I told my family and my solicitors that I needed some time to process what I had seen, so I switched my phone off and just started driving," Buzzard-Quashie says.

She left London in her Range Rover. In the boot of her vehicle, in a brown envelope, was her copy of the graphic CCTV footage from the Met Police.

The following day Buzzard-Quashie says she awoke in her car on the outskirts of Northampton feeling confused.

She could not find her phone and felt a pain in her stomach. A member of the public called an ambulance to take her to hospital.

But during the journey, she says she borrowed a paramedic's phone to call her mother and learned her family were worried and had reported her missing to the Met.

Fearing another police encounter, she says she left the hospital before being admitted and returned to her car, which was parked at the gateway to Althorp House - where Diana, Princess of Wales is buried.

There, she encountered a police officer who had tracked her down.

"He told me there was a concern for my welfare," Buzzard-Quashie says, "I thanked him but said I didn't want to talk about it, and I knew I was under no obligation to stay, so I got into my car."

In the police body-worn video, she can be seen driving normally while being followed for 16 minutes first by one police car, then a second.

No attempt is made to pull her over with blue lights.

Instead, a spike strip was thrown into the road in front of her car. She drove around it and then stopped.

The pursuit log, obtained by the BBC, reveals how a police helicopter was deployed and preparations were made to deploy armed response vehicles had she made it to the M1 motorway.

"The more they tried to stop me getting home, the more I realised I was in trouble," Buzzard-Quashie says.

"Something was seriously wrong. I'm thinking they want the [CCTV] footage in the back of my car."

Radio logs shared with the BBC reveal officers from the Met were in regular contact with their counterparts in Northamptonshire, appearing to press the urgency of apprehending Buzzard-Quashie by claiming she "lacked capacity" and had "indicated she will try [to kill herself]".

The BBC asked the Met to explain the basis for this intelligence, but it refused to comment.

Meanwhile, officers on the ground appeared to be confused by the level of interest in her.

When instructed by a senior officer to "consider using Section 136 powers" to detain her under the Mental Health Act, one of the officers points out: "She presents as having capacity and has made no intent or threats to harm herself."

When the same officer is then told to "lock her up for failing to stop", he replies: "Er, we can try that, but at no point have I lit the blue lights of the vehicle up."

According to the guidelines, police conducting a welfare check are limited to reporting information and seeking a medical assessment if necessary, while armed officers are usually only deployed to deal with dangerous individuals carrying a lethal weapon.

Buzzard-Quashie was arrested while walking along the A428 for failing to stop in her car.

Body-worn video shows her being wrestled to the ground by two officers.

"I'm an eight-stone woman and the biggest male officer was kneeling on my back," she says.

"The female officer was at my top half, and my face was being rubbed into the stinging nettles.

"Even though I was in a lot of pain, I was really concerned about my CCTV footage."

Buzzard-Quashie was handcuffed while on the ground and taken to Northamptonshire Criminal Justice Centre, where she was searched, charged and remanded into custody.

"It was a very degrading situation and there was no care about my welfare," she says.

Her belongings were taken by the custody sergeant, which is standard practice after an arrest. But when her brown envelope was returned the following day, she says the graphic CCTV recording of her using the toilet was missing.

"I was very upset that my [footage] had been stolen," says Buzzard-Quashie, although she told the BBC that she had downloaded the footage the night before her arrest.

After she was released, the case against her was dropped by the Crown Prosecution Service.

Several policing or missing persons experts and former senior officers have voiced concerns to the BBC about Buzzard-Quashie's treatment.

"The whole arrest tactic was disproportionate," says Dr Emma Cunningham, a criminology lecturer at the University of East London.

She added the use of restraint had the potential to cause "quite a bit of trauma".

"If police want to speak to someone about their wellbeing, then you wouldn't have a helicopter and a stinger," she says.

"Why handcuff her? Why would there be any need for that kind of force?

"She hasn't committed an offence, and she's not doing any harm to herself or anyone else. She seems to be 'with it', they've said, and is driving perfectly normally."

We asked both police forces if, as Buzzard-Quashie claims, the real reason officers detained her was to take the graphic Met Police CCTV footage she was carrying, but they declined to comment due to the ongoing legal action.

However, Northamptonshire Police told a court all of Buzzard-Quashie's belongings were returned to her.

Buzzard-Quashie was released with no further action and immediately requested the body-worn video of her arrest for failing to stop in Northamptonshire, to which she is entitled under the Data Protection Act.

It was the start of a four-year legal saga.

"I wanted justice and knew that without that indisputable evidence [of my wrongful arrest], it would be my word against the 30 or so officers that dealt with me that day," she says.

In witness statements prepared for the courts, Chief Constable Balhatchet insisted all of the body-worn video had been released to her or deleted.

But eventually her lawyers obtained audit logs revealing such claims to be false - not only were there more videos, but they had been accessed by the police dozens of times.

"It became apparent they were watching the body-worn video, then days later making sworn witness statements saying it doesn't exist," says Buzzard-Quashie.

The revelations prompted the police to release more recordings in November.

Balhatchet admitted contempt of court and apologised in person to the Court of Appeal for the "appalling failures" of his force, which Lord Justice Fraser described as "wilfully disobedient".

He was ordered to pay a £50,000 fine and to date, more than £250,000 in legal costs.

"People need to know that when you sign a statement to the civil courts, it's got to be true to the best of your knowledge," says Buzzard-Quashie's solicitor Marc Livingston.

"The amount of witness statements in this case that were not accurate was just astonishing. After all, this is the police - you're supposed to be able to trust them."

Buzzard-Quashie is now seeking seven-figure damages at the High Court from the Commissioner of the Met Police, Sir Mark Rowley, and Balhatchet, variously alleging assault, malicious prosecution, trespass to goods and a breach of her human rights.

Both forces contest the claims.

In its defence to the court, Northamptonshire Police insisted all Buzzard-Quashie's property was returned to her, adding "it would have been obvious" she was required to stop during the welfare check and insisted its use of force was lawful.

The Police, Fire and Crime Commissioner for Northamptonshire, Danielle Stone, told a panel she and Balhatchet were not made aware of the proceedings for contempt until October last year, but acknowledged there were "huge questions" about the chief constable's apparent lack of awareness, and has launched a review.

The BBC has asked for comment from Balhatchet's predecessor, Nick Adderley, who was chief constable of Northamptonshire Police at the time of the incident in 2021.

Adderley is charged with fraud, misconduct in public office and making a false witness statement in relation to a separate matter and is due to stand trial in 2027.

With extra reporting by Laurence Cawley

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