Battlefield is the first serial of the 26th season of the British science fiction television series Doctor Who, which was first broadcast in four weekly parts on BBC1 from 6 to 27 September 1989.
In the serial, Morgaine (Jean Marsh), a sorceress from another dimension, summons the planet-devouring Destroyer (Marek Anton) in England, where she also seeks to take the sword Excalibur for herself.
Part 1's 3.1 million viewers represent the lowest ratings of any full episode of Doctor Who[2] In response to a distress signal, the Seventh Doctor and Ace materialise the TARDIS near Lake Vortigern in England, where a UNIT convoy led by Brigadier Winifred Bambera is transporting a nuclear missile.
At the Gore Crow hotel, they meet a young woman called Shou Yuing and a knight, Ancelyn, who addresses the Doctor as "Merlin".
The first director approached to handle Battlefield was Graeme Harper, who had previously directed The Caves of Androzani and Revelation of the Daleks in 1984 and 1985 respectively.
[6] During recording of the sequence where Ace is trapped in the glass water tank, the glass cracked, causing Sophie Aldred to sustain minor cuts to her hands and creating a major safety hazard as water flooded out onto the studio floor, across which live wires were running.
The moment when the tank first cracked can be seen in Part Three as the Doctor struggles with the controls and Ace is lifted clear of the water.
[8] Other guest stars making return appearances in Battlefield include Jean Marsh, who over twenty years earlier had played Princess Joanna in The Crusade and later, companion Sara Kingdom in The Daleks' Master Plan, which had been, coincidentally, Nicholas Courtney's first Doctor Who story;[9] and June Bland, who appeared in the Fifth Doctor story Earthshock.
[11] Its prologue features the future Merlin Doctor taking the wounded King Arthur aboard the spaceship beneath the lake following the last battle as well as additional information about UNIT and Morgaine's dimension.
The final scene implies that the Brigadier is planning to go with Ancelyn back to the other dimension to help restore order, a similar plot point to the ending of the Eighth Doctor Adventures novel The Shadows of Avalon.
It was released on Region 2 DVD on 26 December 2008 as a Special Edition featuring the original televised story plus a movie-length version featuring extended scenes and new special effects, with its scenes reedited into script order to clarify the story's themes and sequence of events.