In 1963, when Canadian-born film and television producer Sydney Newman, then the newly-appointed BBC head of drama, decided a science fiction programme would be a good fit for a Saturday afternoon slot bridging Grandstand and Juke Box Jury, he could never have anticipated that 50 years later the anniversary of his commission's first broadcast would be marked by a celebratory range of Royal Mail stamps and a merchandise-fest that includes badges, keyrings, coasters, ceramics and other collectibles.

In 2013, Doctor Who, watched in 200 territories, is one of only two programmes to have its own dedicated tab on the BBC Shop home page (the other is Top Gear) and is one of a select number of "superbrands" for BBC Worldwide, the commercial division of the public service broadcaster that seeks to "maximise profits on its behalf".

Seventh series
Doctor Who is the top performing show on BBC America, where viewership of the seventh series of the programme since its 2005 revival (the 33rd season overall) securing a 50 per cent rise in its audience compared to series six. Asylum of the Daleks, the series seven premiere, is the most-watched telecast in the history of BBC America.

This Saturday's special anniversary episode, The Day of the Doctor, seems destined, given many months of advance publicity, to shatter the BBC America record, while denting The X Factor's audience in its home market, where it will be broadcast on BBC One at 7.50pm.

Most significantly, the episode is being broadcast simultaneously around the world to minimise leaks and spoilers – with a 2.50pm eastern daylight time slot and a breakfast-time showing in Australia. It is on track to become the biggest ever global simulcast for a drama.

As for Grandstand and Juke Box Jury, well, not every format can withstand the march of time.