A jury has returned a verdict of "unlawful killing" at the inquest of two children who died of carbon monoxide poisoning at a Thomas Cook-owned hotel in Corfu.
Bobby and Christi Shepherd, aged six and seven, died while on holiday at the Louis Corcyra Beach Hotel in Corfu in October 2006.
The pair died after being poisoned by the fumes, which leaked from a faulty hot water boiler. An investigation found a safety device on the boiler had been disconnected.
An inquest into their deaths at Wakefield Coroner's Court also heard how holes were left in the walls between the outbuilding and the bedroom when air conditioning pipes had been installed.
The coroner at the inquest previously told the jury that a verdict of unlawful killing could be the only one that could be returned due to the "bodged and botched" job on the boiler.
As well as the unlawful killing verdict, the jury ruled that Thomas Cook "breached their duty of care" over the deaths of Bobby and Christi.
The bodies were discovered by a cleaner at the hotel alongside their father, Neil Shepherd, and his partner, Ruth Beatson, who were both in comas but later recovered.
As this is an inquest, no prosecutions will be brought forward unless police believe they have enough evidence to proceed.
In 2010, the hotel manager and two members of staff were found guilty of manslaughter by negligence and sentenced to seven years.
Following the unlawful killing verdict, the children's mother, Sharon Wood said there will "never be true justice" for their deaths.
She said: "While we appreciate there were criminal convictions in Corfu, it is clear that Thomas Cook could and should have identified that lethal boiler.
"Thomas Cook put Christi and Bobby in that bungalow and I will always hold Thomas Cook responsible for their deaths.
"There can never be true justice for the lives of my two innocent children. Their whole lives ahead of them. Rest in peace now, our beautiful angels."
In a statement read out by their lawyer, the family added Thomas Cook should "hang their head in shame".
It continued: "Thomas Cook you are a multi-million pound operation. You take money from families like this family who expect to go on holiday and have the time of their lives.
"They don't expect to return from holiday with their children in coffins because Thomas Cook staff failed to properly check the standards of the hotel they stayed in.
"The jury has found these children were killed unlawfully as a result of criminal negligence.
"No proper explanation has been provided for how this happened. Thomas Cook should hang its head in shame as a result of these deaths."
The CEO of Thomas Cook, Peter Fankhauser, said during the inquest the company does not need to apologise for the deaths as it had done nothing wrong.
"I feel so thoroughly, from the deepest of my heart, sorry, but there's no need to apologise because there was no wrongdoing by Thomas Cook," he said.