It is perfectly legal to employ under 16 year olds, if the employee has a valid Child Workers Permit issued from the council. Having said this, there are some departments in Thorpe Park that require employees to be 16 or over. (R&A, Medical etc).And as for the "not knowing they were 16", this is impossible, unless of course the employees concerned lied about their age at the recruitment stage. (Which is near enough impossible, as a valid document showing D.O.B is required at the assessment/interview stage of any Merlin attraction).