A former school teacher has pleaded guilty to a series of sexual assaults on young boys.
Stephen Douglas-Hogg taught at St Paul's Cathedral Choir School in central London during the 1980s.
The 50-year-old changed his plea halfway through the trial and admitted to 13 counts of indecent assault on five boys aged under 14.
Douglas-Hogg, from Filey, North Yorkshire, will be sentenced at Southwark Crown Court on Monday.
Places at the school, where pupils were selected for their musical or singing talents, were highly sought after as there were no fees for attendance or boarding.
Timothy Devlin, prosecuting, said the housemaster had his "favourites" among the older boys at the school and subjected them to "special treatment".
Douglas-Hogg, was responsible for supervising the boys during activities such as football, cricket, bath times and meal times.
But Mr Devlin said one witness thought Douglas-Hogg was "grooming them to have sex" and became concerned at the amount of time the boys spent in his room.
Other witnesses said Douglas-Hogg had all "the power" at the school, had a "false charm" about him.
Mr Devlin said another witness described the teacher as "a time bomb waiting to go off".
During the 1980s Douglas-Hogg would inappropriately touch boys who had been sent to bed early as a punishment, Mr Devlin said.
He also told the boys to visit him in his room, where he told them to undress and lie on his bed before assaulting them Mr Devlin said.
He added that the young boys saw Douglas-Hogg as a "father figure" and thought they were receiving "special treatments".
Mr Devlin said that as time went on Douglas-Hogg "started pushing the boundaries and became more forceful".
He would touch others in his room and also tried to kiss some of the boys.
Douglas-Hogg, who taught Latin, Greek, and classical history at the school, was arrested in December 2007.