Doctor Who: The Sun Makers (1977)

Another adventure for everyone's favourite time traveller. The vast majority of the population labour in an underground city, crippled by the taxes imposed on them by the autocratic Company. It isn't long before the Doctor is siding with the underground rebel movement, but the need to overthrow the corrupt rulers takes on a new urgency when Leela is captured and sentenced to death by their leader, the sinister Collector...