A former Cunard cruise ship worker has admitted carrying out sex attacks on 13 boys while working as a supervisor for a children's activity area.
Paul Trotter, 34, pleaded guilty to a string of sexual assaults and taking, making and possessing indecent images of children, most of whom were under the age of 13 at the time.
The supervisor made films of himself abusing the children in his care on board three cruise ships, operated by Cunard. He also possessed other indecent images of children he had obtained online.
In a statement Cunard, part of the Carnival Corporation group and owners of the Costa Concordia which ran aground earlier this year, said it was "deeply shocked" by Trotter's "appalling crimes".
It added he had avoided detection despite a number of safeguards, including having had his criminal record checked.
Trotter, from Pontefract, West Yorkshire, appeared at Swindon Crown Court, dressed in a suit and purple tie.
He admitted 12 counts of sexual assaulting a child under the age of 13, one count of sexual activity with a child under the age of 13, five counts of taking indecent images of a child, five of making indecent images of a child and one of possessing indecent images of a child.
The offences were committed from November 2007 to August 2011 when he arrested by Wiltshire Police's child abuse investigation unit.
Judge Douglas Field told Trotter, who was living in Wiltshire at the time of his arrest, he would be held in custody to return before the same court on May 11 for sentencing.
He also ordered him to sign the sexual offences register before he was taken back to prison.
Speaking outside court, Cunard president and managing director Peter Shanks said: "We were first made aware of these serious allegations eight months ago by Wiltshire Police and were deeply shocked by what we were told.
"Since then Cunard has provided full support and cooperation to the criminal investigation, and where possible within the constraints of the legal system, to the families involved.
"Our own feelings of shock are secondary to those of the families directly impacted.
"As a parent myself I can clearly understand the emotional pain and anguish they have suffered and endured since they were contacted by the police investigating this case.
"From the outset, every family impacted by these appalling crimes has had our support, and by partnering with the NSPCC, guidance and help from the experts in the field of child welfare has been offered and accepted.
"Paul Trotter was able to avoid detection despite all of our youth staff, including Mr Trotter, having had their criminal records checked. We have closed circuit TV on board all of our ships, including all of the children's clubs, and our own rules dictate that a minimum of two members of staff are to be with children at all times.
"Our safeguards were strict but sadly did not stop this one individual from managing to circumvent the system and manipulate those around him.
"We are now working with the NSPCC and have already identified changes in three key areas for improvement."
The cruise ship company, which operates the Queen Mary 2, the Queen Victoria and Queen Elizabeth, offering luxurious ocean travel, added it had asked the NSPCC to audit its policies and procedures.
As a result, it has changed its recruitment process, introduced new training and improved on board supervision of the youth centres.
Mr Shanks added: "We will do everything in our power to put in place every possible safeguard for children."
Detective Inspector Nicki Davey, who led the investigation, said: "In August 2011, Wiltshire's child abuse investigation unit received intelligence which highlighted that Paul Trotter, a Wiltshire resident at the time, was in possession of indecent images of children.
"The contents of his computer were examined and revealed that he had filmed himself abusing children in his care.
"Many of these films were made on board three cruise ships operated by Cunard, where Trotter was employed in the children's play zone area. He also possessed other indecent images of children obtained online.
"With the co-operation of Cunard, a great deal of work went into identifying the children to allow us to inform their parents.
"Wiltshire's child abuse investigation unit has fully supported parents throughout this investigation with the assistance of the NSPCC.
"Paul Trotter worked in a position of trust with children. He has abused the trust placed in him by the children and their parents.
"His admission of the charges will mean that the families do not have to experience the distress of a trial. We would like to acknowledge their co-operation and understanding following our visits to them."
John Grounds, director of the NSPCC's child protection consultancy, said: "While nothing will ever excuse Paul Trotter's crimes, his guilty pleas are welcome as this should save his young victims having to re-live their ordeals while giving evidence in court at a later full hearing.
"In the meantime, the NSPCC is working closely with Cunard to help improve its child protection policies and procedures and will be presenting its recommendations very shortly.
"From the outset, Cunard have taken a proactive approach to address any issues arising from this case and we look forward to a continuing relationship with them.
"If anyone has concerns arising from this case they can call the NSPCC on a special helpline number - 0800 980 4502."