Here is a timeline and video run-through of events in the case of Pc Andrew Harper.

Warning distressing footage and strong language in video.

- August 15 2019, 4.50pm: Henry Long, Albert Bowers, Jessie Cole and Thomas King arrive at the home of Peter Wallis in Bradfield Southend, Berkshire, to steal his £10,000 quad bike.

They are confronted by Mr Wallis and leave empty handed.

- 11.10pm: Long, Bowers and Cole return to Mr Wallis's house and, over 15 minutes, steal his quad bike.

It is attached to a Seat Toledo by a strap and ridden by Cole.

- 11.17pm: Mr Wallis makes a 999 call to report a theft in progress. He says: "I've got four masked men outside my house and they've got weapons."

Pc Harper and his crew mate Pc Andrew Shaw are nearby in a BMW car, having already finished their shift.

- 11.28.17: The officers get a first glimpse of the Seat headlights approaching their car in Admoor Lane.

The vehicles stop, facing each other around 5m apart.

Eight seconds later, Long mounts the verge as he drives around the police car.

Cole is on foot behind the Seat. Having unhitched the quad bike, he tries to get back in the Seat.

Cole runs past the police car, pursued by Pc Harper, and dives through the Seat passenger window, the Old Bailey is told.

- 11.28.46: Pc Harper has almost reached the car and Cole but runs into the loop of the strapping trailing from the boot.

 Reading Chronicle: File screengrab taken from video dated 15/08/19 issued by Thames Valley Police of a quad bike which was attached to a Seat car when stopped by Pc Andrew Harper and Pc Andrew Shaw whilst responding to a burglary in progress near Stanford Dingley in Berkshi 

He is dragged away as Long accelerates off, jurors are told.

The whole incident takes around 30 seconds.

- 11.29.55: More than a minute after Pc Harper's disappearance, Pc Shaw stops to recover Pc Harper's stab vest, which was in two parts in the road.

- 11.30.17: Pc Harper's body is found by Pc Christopher Bushnell in Ufton Lane.

He has been dragged just over a mile for 91 seconds before he is dislodged the other side of the A4.

It means Long has driven an average of 42.5mph, the court is told.

Pc Bushnell alerts his colleague Pc Andy Kemp to the figure in the road and sets off in pursuit of the Seat.

- 11.31.40: Pc Shaw reaches the A4 and Ufton Lane, where he finds his colleague having followed a trail of road marks, blood and body matter.

Meanwhile, Long heads towards Ufton Court but gets stuck behind a wedding coach and turns back, forcing Pc Bushnell to take evasive action to avoid a head-on collision, the court is told.

The Seat is then driven at speed towards Four Houses Corner and Pc Bushnell loses sight of it, jurors hear.

- 11.30pm: The National Police Air Service (NPAS) helicopter is directed to the Four Houses Corner travellers' site.

- 11.42pm: The NPAS helicopter reports seeing, using thermal imaging, the "very, very hot" Seat on the site, with people standing around another car in an adjacent plot.

- 11.45pm: Pc Harper is pronounced dead in the road where he was found.

- August 16 2019, early hours: The defendants are arrested.

In all, 10 males at the caravan site are detained and mobile phones seized.

- August 19: One of the males, Jed Foster, 20, is charged with murder and the theft of a quad bike.

- September 12: By now, police have analysed mobile phone data placing Long, Cole and Bowers at the scene, and ruling out Foster, despite initial evidence suggesting he might have been involved.

Reading Chronicle: File screengrab taken from video issued by Thames Valley Police dated 14/08/19 at 00.11 of (left to right) Albert Bowers, Tom King and Henry Long at an Esso petrol station in Reading and shown at the Old Bailey in London as evidence in the trial for the m

- September 18: Long, Cole and Bowers are charged with murder.

- September 19: Charges against Mr Foster are dropped.

- October 14: Pc Harper is laid to rest at a funeral at Christ Church Cathedral on St Aldate's, Oxford.

- January 7 2020: Long pleads guilty to manslaughter.

King, 21, from Basingstoke, admits conspiracy to steal a quad bike.

- March 9: Bowers and Cole plead guilty to conspiracy to steal the quad bike, which Long also already admitted.

- March 10: The case is opened against the three teenagers at the Old Bailey. They all deny murder.

- March 23: As the country goes into lockdown, Mr Justice Edis discharges the jury.

- June: A retrial gets under way at the Old Bailey under strict social distancing rules.

- July 1: Jurors visit the site in Berkshire where Pc Harper was killed.

- July 24: The defendants are acquitted of murder but Bowers and Cole are found guilty of manslaughter.