A former paddleboard firm owner who caused the deaths of four people in south west Wales has been refused permission to appeal against her sentence.
Paul O'Dwyer, Andrea Powell, Morgan Rogers and Nicola Wheatley died after paddleboarding in "extremely hazardous conditions" on the Western Cleddau river in Haverfordwest, Pembrokeshire in October 2021.
Nerys Bethan Lloyd, 39, an ex-police officer from Port Talbot, pleaded guilty to gross negligence manslaughter in March 2025 and was jailed for 10 years and six months.
Three Appeal Court judges rejected David Elias KC's submissions that the sentence was "manifestly excessive".
Lady Justice May told the court they found the trial judge's approach to have been proportionate given the number of victims.
At the sentencing in April 2025, the court heard Lloyd was unqualified to lead a paddleboard tour of this kind.
Neither Lloyd nor co-instructor O'Dwyer were qualified to lead the tour, and Mrs Justice Stacey criticised the "abysmal" approach to health and safety.
Citing Lloyd's police and RNLI training, the judge said she "knew better", although acknowledged she was "horrified" at what happened.
The group of seven participants, led by Lloyd and O'Dwyer, set off after 09:00 BST on 30 October 2021.
Three participants died along with O'Dwyer.
During the sentencing hearing, the court heard there had been heavy rain in the days before and "the river was in flood conditions" with a "visibly strong current".
The court was also shown photos of a weir the group was trying to navigate.
This included a section called fish pass, which was 11m (36ft) long and on an incline of about one in seven, or 14%.
The court was shown conditions on the weir on the day of the incident, with the prosecution explaining it showed "immense turbulence" of the water.
At the sentencing in April 2025, Stacey said the group "fell down the face of the weir" in no more than 20 seconds.
They were sucked into a hydraulic jump - or spin - a recirculating flow similar to a washing machine.
She added: "The ankle leashes attached to the boards of those stuck in the hydraulic spin, which are totally unsuitable for fast-flowing water, made it even harder for them to get free."
Stacey said that the "four participants were not wearing wetsuits and one had decided that a life jacket would not be necessary".
She added there had been "no safety briefing" beforehand, none of the participants had the right type of leash for their boards in these conditions and Lloyd did not have any next of kin details.
O'Dwyer initially exited the river safely, but then re-entered the water in an attempt to rescue the others.
O'Dwyer, from Port Talbot, Rogers, from Merthyr Tydfil, and Wheatley, of Pontarddulais, Swansea county, all died at the scene.
Powell, from Bridgend, died in hospital on 5 November 2021, about a week after the incident.
At the sentencing the judge said it was clear to her Lloyd intended for the group to go over the weir down the fish pass if possible "which would be more interesting" than carrying the boards round the weir.
O'Dwyer had researched alternative routes, but all were "dismissively rejected by you", the judge said.
O'Dwyer deferred to Lloyd as the company owner to decide the final route but raised valid concerns, such as the drop over the weir.
Stacey said Lloyd's interest "seemed to be more in an exciting route than safety" and it was clear from CCTV she went straight down the middle of the weir rather than making any attempt to get to the side.
She added she showed "a blatant disregard for a very high risk of death".
Her lawyer told the court Lloyd took "full blame for the mistakes" that led to the deaths. He said there was a plan to get out of the water ahead of the weir but the force of the water meant she and the others were carried over it.
