 Broadcasting hours on British television were tightly controlled by the Postmaster General in the 1960s, and, for the majority of the 1960s, weeknights on BBC Two were limited to 7 hours of programming in a day (excluding sport, political conferences, schools, religion and adult education which were exempt from the restrictions).As BBC Two would normally only air for 30 minutes in the morning at 11 am with Play School, this meant 6.5 hours were left over, with BBC Two normally starting their evening at 7.00pm, it meant Late-Night Line-Up could remain on the air until 1.30am if they so wished.It never happened, but the freedom for discussion, without worrying about exceeding the broadcasting day allowance made the programme very popular, especially with those who enjoyed watching television late at night, as BBC One and ITV generally closed down by 11.45pm each weeknight.