Summary:
- Cain Byrne sentenced to 11 years and six months for killing elderly cyclist Graham Slinn while under the influence of nitrous oxide.
- Byrne was driving without a license, inhaling nitrous oxide from a balloon before and after the incident.
- The incident occurred on April 4, 2025, when Byrne ran a red light at 80 mph, striking Slinn on a pedestrian crossing.
- Byrne fled the scene and was later caught and pleaded guilty to causing death by dangerous driving.
- He received a five-year extended licence term and a 17-year, eight-month driving ban.
- The case shed light on the dangers of legal highs and reckless driving, prompting grief and public outcry.
A 20-year-old man has been sentenced to more than a decade behind bars after killing an elderly cyclist while driving under the influence of nitrous oxide near Rotherham, South Yorkshire. The incident, which occurred on April 4, 2025, resulted in the death of 81-year-old Graham Slinn and prompted renewed discussion around road safety and so-called “legal highs.”
Cain Byrne, who had never held a driving licence, was inhaling nitrous oxide from a balloon before and after the moment he accelerated his silver Vauxhall Astra through a red light at high speed. According to court proceedings, he was travelling at up to 80 miles per hour in a 50 mph zone when he struck Mr Slinn, who was walking his bicycle across a pedestrian crossing on the A57 near Todwick.
The impact of the collision, according to witnesses and investigators, threw Mr Slinn around 15 feet into the air. He was pronounced dead at the scene. Byrne fled immediately after the crash, abandoning the car nearby and initially evading authorities.
At Sheffield Crown Court, Byrne pleaded guilty to causing death by dangerous driving. On July 21, he was sentenced to 11 years and six months’ detention in a young offenders institution. In addition to the prison term, Judge Jeremy Richardson KC imposed a five-year extended licence period upon Byrne’s release and disqualified him from driving for 17 years and eight months.
“Your criminal behaviour is ingrained and dangerous,” Judge Richardson told Byrne during sentencing. “You pose a significant risk to the public and must be treated accordingly.”
The court heard that Byrne had a history of offending, including driving-related infractions, despite having never been legally permitted to operate a vehicle.
Footage submitted as evidence showed Byrne inhaling nitrous oxide while driving around a retail park prior to the collision—and again after the incident. Commonly referred to as laughing gas, nitrous oxide can impair reaction time and coordination. While it is legal for certain medical and industrial uses, its recreational consumption has drawn increasing attention from road safety campaigners and legislators.
Mr Slinn’s family described him as a vibrant and active individual who continued to work as a lorry driver well into his 70s. In a statement read to the court, they said his death was “100 percent avoidable” and “doubly cruel” because of the reckless circumstances that led to it.
“This act has taken away someone who was full of life and energy, someone who meant the world to us,” the statement continued. “The grief is magnified by the senselessness of it all.”
Byrne will serve two-thirds of his sentence in custody before becoming eligible for release. His extended licence terms mean he can be recalled to prison if he breaches any conditions once released.
Authorities reiterated the dangers of driving under the influence of disorienting substances, including nitrous oxide, and reminded the public of the severe consequences such behaviour can have.
Background:
Here is how this event developed over time:
- April 4, 2025: 20-year-old Cain Byrne struck and killed 81-year-old cyclist Graham Slinn in a hit-and-run incident on the A57 near Todwick, South Yorkshire.
- April 4, 2025: Byrne, who had no driving license, was inhaling nitrous oxide from a balloon before, during, and after the collision.
- April 4, 2025: Driving at an estimated 70–80 mph in a 50 mph zone, Byrne ignored a red light at a pedestrian crossing where Mr. Slinn was walking his bicycle.
- April 4, 2025: The collision threw Mr. Slinn approximately 15 feet into the air; he died at the scene.
- April 4, 2025: Byrne fled the scene immediately following the crash.
- Prior to July 2025: Byrne pleaded guilty to causing death by dangerous driving at a pre-trial hearing.
- July 21, 2025: Sheffield Crown Court sentenced Byrne to 11 years and 6 months in a young offenders institution, with a further 5-year extended license period.
- July 21, 2025: Byrne also received a driving ban of 17 years and 8 months.