Alan Luckhurst, 36, from Surrey, had his six-month prison term, suspended for 18 months, overturned by the Court of Appeal after his case was reviewed under the Unduly Lenient Sentencing scheme.
Luckhurst will now serve two years and six months in prison.
The Solicitor General Michael Tomlinson KC MP said:
"Luckhurst's vile crimes are only exacerbated by the trust placed in him to look after young students on work experience.
"The severity of his appalling behaviour has now been recognised by the courts, and he will spend time in prison for crimes that have left a devastating impact on his victims."
Luckhurst was sentenced on 27 March 2023 at The Crown Court at Kingston-upon-Thames. He was found guilty on eight counts of sexual assault and two counts of causing a person to engage in sexual activity without consent.
He was given 6 months' imprisonment suspended for 18 months with a 35-day accredited programme and 30 days Rehabilitation Activity Requirement.
