O is for... Oracle

Oracle was the name adopted by the computer of the Minyan spaceship P7E. This race had almost destroyed itself in a civil war, and the P7E had set off with their race banks so that a new start could be made on Minyos II. However, the ship never arrived, and so the R1C was sent to find it. The Time Lords had given the Minyans the technology to prolong their lifespans, and the quest to find the missing ship lasted for thousands of years. The vessel had entered a region of space where gravitational forces caused it to become the core of a new planetoid.

During that time the P7E's computer had developed a unique personality which became deranged over time. Calling itself Oracle, it corrupted the Minyan society, which formed a religion which came to worship the computer. Two of its servants underwent cybernetic transplants to become the semi-robotic Seers, who acted as its priests. Others  became supervisors, whilst the bulk of the population were enslaved. Regular sacrifices were conducted to maintain a stable population.

The Doctor helped Jackson, commander of the R1C, locate the P7E. Together they freed the Minyan slaves whilst the Oracle tried to destroy them by surrendering fake race banks - replacing the real thing with powerful fusion bombs.

Believing itself infallible, Oracle failed to provide a contingency plan when the Doctor swapped the objects back. Unable to defuse them, it and its loyal followers were blown up by the bombs after the R1C had departed.

Voiced by: Christine Pollon. Appearances: Underworld (1978).

• Cardiff born Pollon had been a regular on the BBC's fashion magazine soap Compact in the early 1960's and much of her work was in radio.
• She was the wife of actor Donald Hewlett, who played Hardiman in The Claws of Axos but is best known for his comedy roles, chief of which was as the concert party CO in It Ain't Half Hot Mum.
• The story is basically a sci-fi version of Jason and the Argonauts, with additional Greek mythology blended in. At Delphi, on the slopes of Mount Parnassus, was a woman known as the Pythia who foretold the future. There was a lengthy wait for a consultation with the Oracle, and expensive sacrifices were expected. Her pronouncements tended to be cryptic, however, and open to interpretation. A set of priests who attended her acted as interpreters for her words. Delphi lies on an active geological fault and her cave would have filled with gasses, which probably explains those cryptic pronouncements.