The father of two children who died from carbon monoxide poisoning while on holiday in Corfu blamed Thomas Cook for not inspecting the boiler.
Neil Shepherd told Wakefield Coroners’ Court that he ‘firmly believed’ they would be alive if the tour operator had inspected the faulty boiler.
An inquest heard earlier how a member of hotel staff might have turned off a boiler safety device that led to the deaths of Christianne Shepherd, 7, and her brother Robert, 6 in October 2006.
The family arrived at the Louis Corcyra Beach hotel on 23 October after booking with Thomas Cook.
The children complained of feeling unwell on 25 October and were found dead the following day by a chambermaid. Mr and Mrs Shepherd were found in a coma.
Post-mortem tests revealed carbon monoxide levels in the children’s bloodstreams were 56.8 and 60.7% respectively. Any level above 50% is deemed fatal.
Mr Shepherd told the court: "I firmly believe my children would be here today if Thomas Cook had carried out an inspection of those boilers."
The children’s mother, Sharon Wood, added: "I want to look further up the chain of command in Thomas Cook.
"I want to know why those gas boilers were not identified, why they were not serviced regularly.
"This is not just a difference of local standards abroad. This is gross negligence."
The inquest was delayed until this week due to legal proceedings in Greece, which led to the jailing of members of the hotel staff.
Thomas Cook was cleared of responsibility for the deaths and, in 2013, it was awarded damages against the hotel’s owner.
