A look at the complex production of the Doctor Who story Underworld, with particular emphasis on the difficulties in achieving the bluescreen virtual studio sets.
| Actor | Role |
|---|---|
 Richard HefferNarrator | Narrator |
 Anthony ReadNot listed | Not listed |
 Bob BakerNot listed | Not listed |
 Dave MartinNot listed | Not listed |
| JJonathan NewthNot listed | Not listed |
| NNorman TiptonNot listed | Not listed |
| DDick ColesNot listed | Not listed |
 Mitch MitchellNot listed | Not listed |
 Graham Williams(archive footage) | (archive footage) |
| NNorman Stewart(archive footage) | (archive footage) |