Full Breakdown
Driver’s Nitrous-Oxide Use and Speed Lead to Cyclist’s Death in Hackney
By Drooid · · How we work
Fatal Collision in Hackney
On the evening of September 10, 2023, Tiffany Treanor-Johnson, 27, inhaled nitrous oxide—a class C drug—before getting behind the wheel of her Audi in Hackney, east London. While travelling at 53 mph in a 20 mph zone on Kenworthy Road, she struck cyclist Harry Webb, 27, a master’s student at the London College of Contemporary Music. Webb suffered a traumatic head injury and died days later in hospital. Police found fragments of nitrous-oxide balloons in Treanor-Johnson’s car after arresting her at the scene.
Legal Outcome
Snaresbrook Crown Court sentenced Treanor-Johnson to 10 years and nine months in prison and imposed a 10-year driving ban. The court also recorded Treanor-Johnson’s earlier denial of the charge before she admitted guilt in April 2024.
Driver’s Impairment and Speed
Prosecutor Fiona Robertson testified that the nitrous-oxide inhalation occurred shortly before the crash and that the driver’s speed was more than double the legal limit. The court heard that after the impact Treanor-Johnson mounted the pavement, collided with a red Citroën, and that the Citroën driver, Brenton Henry, seized her car keys to prevent her from leaving the scene. One passenger in the Audi was observed taking a bag from the vehicle before exiting.
Background of the Victim
Harry Webb was described by family and court witnesses as an “intelligent and wonderfully caring” drummer who had moved into new accommodation that day to begin his second year at the London College of Contemporary Music. He was speaking with his father on the phone at the time of the crash, thanking him for his support.
Official Statements & Responses
Judge Rosa Dean’s sentencing remarks emphasized personal responsibility and the likely impairment from nitrous-oxide use. The Metropolitan Police confirmed that fragments of nitrous-oxide balloons were recovered from the vehicle and that Treanor-Johnson was arrested on-scene.
Community Memorial
A “ghost bike”—a painted bicycle serving as a roadside memorial—was installed at the junction where Webb was killed, accompanied by a photograph of the victim. The memorial has become a focal point for grieving friends, family, and cyclists advocating for safer streets.
Data & Statistics
- Speed recorded: 53 mph (court evidence)
- Legal speed limit: 20 mph
- Sentencing: 10 years 9 months imprisonment, 10-year driving disqualification
- Drug involved: nitrous oxide (class C)