A "dangerous predator" who sexually abused an eight-year-old boy while on a residential trip in South Yorkshire has been jailed for four years.
Former teacher Adam King, 38, from Oxfordshire, assaulted the child in October 2017 while he was volunteering for a diabetes charity, police said.
He admitted one charge of sexual assault at Sheffield Crown Court.
Diabetes UK said it was "deeply sorry" and would be carrying out an "independent learning review".
King, of Goldcrest Way, Bicester, was also placed on the sex offenders register for life and given a lifetime sexual harm prevention order.
Det Con Kath Coulter, of South Yorkshire Police, said King had "not shown any remorse for his crimes".
"His refusal to admit his guilt until today has caused significant distress to the victim and his family."
She commended the victim's "tremendous courage and strength of character" throughout the investigation.
"It is thanks to the bravery of this child that this dangerous predator is now behind bars."
Ms Coulter said King had "wholly abused the position of trust and responsibility" he held as a volunteer with Diabetes UK.
Diabetes UK said: "We are deeply sorry for what the family at the centre of this case has been through and we would like to acknowledge their bravery and resolve in bringing this case to court.
"Nothing is more important to us than ensuring the safety and wellbeing of children on our events."