It follows in a long tradition of popular British television programmes producing short, light-hearted specials for such telethon events.

Most notable amongst the many connections between "old" and "new" versions is the fact that it showcases the first televised Doctor Who script by Steven Moffat, the first post-production work of The Mill on the programme, the only time a woman produced an episode of the programme between Verity Lambert and Susie Liggat, and the final performance by the longest-serving Dalek vocal artist, Roy Skelton.

The planet is in ruins, and was once the home of a now-extinct race of supremely-enlightened beings shunned by all because they used flatulence as their means of communication.

The Master appears, gloating that he travelled a century back in time, and persuaded the architect of the castle to put in a secret death trap.

The Doctor informs the Master, having calculated that he "has saved every planet in the known universe a minimum of 27 times", and having grown tired of battles with aliens and "the endless gravel quarries", that he is retiring, having found a companion – Emma – with whom he has fallen in love.

However, the Doctor had already bought the architect that dinner, so when the Master pulls the lever, a trap door opens beneath him instead.

The Master throws himself at the Doctor but falls into the sewers again, and immediately bursts in again, another 312 years older and with a walking stick.

Having spent a total of 936 years in the sewers, he returns using a zimmer frame (walker) and is easily outpaced by the slow moving Daleks.

Forced to fix the Dalek weapon, he is also electrocuted and becomes a shy, middle-aged and overweight Doctor (Jim Broadbent).

Due to the Zektronic energy beam's ability to disable the regenerative process, the Doctor permanently dies.

However, the practical unavailability of these soundtracks forced the show's musical director, Mark Ayres, to use material mostly from the Fifth Doctor's era.