The mother of a teenage girl killed in a car crash has said no prison time “will ever feel adequate” after the drink-and-drug-driver jailed over her daughter’s death had his sentence increased by the Court of Appeal.

Danielle O’Halloran, 36, said she hoped Keilan Roberts can “do some good” with his life after serving his newly extended jail term for causing the death of 17-year-old Chloe Hayman by careless driving.

She also hoped the increased sentence would deter people driving a vehicle under the influence of alcohol or drugs, sending the message: “just don’t do it”.

Roberts, now 22, admitted four offences relating to the death of Chloe, who was a passenger in his car when it crashed in the early hours of July 24 last year.

He had consumed alcohol, cocaine, ketamine and ecstasy before getting behind the wheel of his Skoda Octavia following a night out in Pontypridd, south Wales.

He was originally jailed at Cardiff Crown Court for three years and nine months, but following a challenge from the Attorney General’s Office (AGO) this was increased by the Court of Appeal on Friday to five years and three months.

Reacting to the appeal ruling, Miss O’Halloran told the PA news agency: “We will always live with a life sentence without Chloe.

“We are dealing with that loss every single day from the selfish act.”

She later added: “Sadly no amount of sentence will ever feel adequate for the loss of Chloe.

“However, following the appeal hearing yesterday, the increase to the sentence is positive news following a long and upsetting process to get to where we are.

“I can only hope that this increase in sentence goes some way to act as a deterrent to anyone thinking of getting behind the wheel under the influence of alcohol or drugs. Just don’t do it.”

At his original sentencing, Cardiff Crown Court was told Roberts, of Rhymney, had not met Chloe before the night of the crash and offered to drive her to her home after arguing with his girlfriend.

Roberts lost control of his car in the village of Fochriw, leaving Chloe, from Mountain Ash, with fatal chest injuries. She died at the scene.

He pleaded guilty to four counts of causing death by careless driving while under the influence, with each charge reflecting the substances he had taken.

“It’s a hard pill to swallow. I’m just gutted she can’t enjoy her life”, Miss O’Halloran said of her daughter, adding: “She was my all”.

Chloe’s mother said “funding needs to be given to the police for more drug testing equipment on the side of the road”, arguing that this could have deterred Roberts from driving under the influence.

This additional time will only serve for a longer period of reflection for him to think about his ways, and I sincerely hope, change his ways, and remember that this never had to happen

According to written arguments from the AGO, a pre-sentence report said Roberts had “a history of drug and alcohol misuse from his teenage years” with there being “some evidence of a history of driving having consumed alcohol, though this had not led to any convictions”.

The AGO said that, within the 20 months leading up to the collision which killed Chloe, Roberts had failed roadside breath tests for alcohol on five occasions, “though later evidential readings had been within the prescribed limit”.

Miss O’Halloran said of Roberts: “I just hope moving forward he can just do some good, be sorry, do the things he needs to do to change his life and show his family that he’s not that person anymore.”

She later added: “This additional time will only serve for a longer period of reflection for him to think about his ways, and I sincerely hope, change his ways, and remember that this never had to happen.”

The court’s decision to increase the sentence should serve as a strong warning that reckless behaviour will be punished to the full extent of the law

At a Court of Appeal hearing in London on Thursday, the AGO challenged the original sentence as being “insufficient”.

Lord Justice Popplewell, sitting with Mr Justice Lavender and Mr Justice Bryan, ruled on Friday there had been an “error” in sentencing judge David Wynn Morgan’s approach in relation to guidelines and the level of Roberts’ intoxication.

The judges also banned Roberts from driving for an extended period of 12 years and seven-and-a-half months.

Jeffrey Jones, representing Roberts, said the original sentence passed was proportionate, adding: “The effect of this crime clearly is going to be devastating to Chloe’s family. This offender will carry the memory of what he’s done for a very long time and his remorse is genuine.”

At sentencing, the court was told Roberts had no previous convictions and had experienced a “fractured and sad childhood”.

Solicitor General Michael Tomlinson said: “When you get behind the wheel of a car while under the influence, you are not only putting yourself in danger but your passengers and everyone else on the road.

“The court’s decision to increase the sentence should serve as a strong warning that reckless behaviour will be punished to the full extent of the law.”