Harper worked as a floor assistant on the BBC One sci-fi classic in the 1960s – before moving on to directing episodes in the 1980s and again in the noughties after Russell T Davies regenerated the Doctor.
Harper started young in show business. At nine, he went to the Italia Conti stage school on Saturday mornings for elocution lessons. He liked it so much that he pleaded with his parents to send him to the school, but the fees were a problem. The solution was for the young Harper to take on acting roles to pay his way.