Doctor Who has had several radical reinventions over the years — when it stopped being about Ian and Barbara, when the Doctor first regenerated, when it became an Earth-bound show during Pertwee’s time, when it stopped being on TV altogether and became a series of books…

Most of the time, the programme has a tendency to revert back to something like the mean, but each time it retains some of the new with the old. Steven Moffat’s reinvention of the programme is, one suspects, another time when this will be the case.