A woman attacked by a now struck-off Ruislip police officer four years ago, has been found dead in her prison cell.

Shocking CCTV images captured Sarah Reed, 32, being punched and dragged by her hair after being arrested on suspicion of shoplifting at a London Uniqlo store in 2012.

PC James Kiddie, who was dismissed without notice from the Metropolitan Police after being convicted of assault, was slammed as a “blow to the reputation” of the force.

An investigation is now underway after Ms Reed was found unresponsive and later pronounced dead in Holloway Prison last month.

According to civil rights campaigner Lee Jasper, she was being held on remand over an incident in a hospital where she was being treated for mental health problems.

A Prison Service spokesperson told The Mirror : “HMP Holloway prisoner Sarah Reed was found unresponsive in her cell at 8am on January 11.

“Prison staff attempted CPR, but she was pronounced dead shortly after.

“As with all deaths in custody, the independent Prisons and Probation Ombudsman will conduct an investigation.”

CCTV showed the moment PC Kiddie beat Sarah Reed

PC Kiddie was sacked in 2014 for gross misconduct after bosses were said to left "extremely shocked" by footage of his attack on Ms Reed.

He can be seen trying to pull the woman's hair as she tries to fight him off before dragging her to the floor and delivering the blows.

A Westminster Magistrates court trial heard that Kiddie was called out to the Regent Street branch of the clothing store Uniqlo in central London by the store's security.

He told jurors that Ms Reed had bitten him on the finger and claimed that she had HIV.

Kiddie, 45, was sentenced to a community order following the attack in November 2012.

He lost an appeal in April 2014.

The Met said Kiddie, from Ruislip, was dismissed without notice by a gross misconduct panel.

Westminster Borough Commander Chief Superintendent Paul Rickett said: “Police officers join the Met to protect and serve the public and I was extremely shocked to learn and indeed see what happened."

"Where an officer's behaviour falls short of the very high standards that we and the public expect of them, then it is only right that they are held to account and PC Kiddie has paid for his actions today.

"Behaviour such as this casts a shadow over the thousands of officers who are on duty right now demonstrating bravery, compassion, integrity and professionalism."

Kiddie was previously investigated by the police watchdog, the Independent Police Complaints Commission, for deploying tear gas during protests in Oxford Street in January 2011.