P is for... Penley

Computer expert working at Britannicus Base who went into self-imposed exile after frequent arguments with his boss, Clent. The world was in the grip of a new Ice Age, and the base was one of several across the globe attempting to hold the glacial advance at bay. Elric Penley's disagreements with Clent revolved around the latter's obsessive reliance on its computer, despite his own expertise in this area. He felt that human instinct and feelings had to be applied to any situation. 

On leaving the base, he found a refuge in an abandoned botanical museum, which was also home to a scavenger named Storr. He had a profound dislike of science, believing it responsible for the global catastrophe.

Clent's deputy, Miss Garrett, kept discreet contact with Penley - hoping that he might one day return to the fold. She could see how her leader, whom she greatly admired, was struggling to cope with the pressures of command.

When the Doctor arrived at the base and immediately diagnosed a computer problem, he was given Penley's role - but advised that Clent really ought to get his expert back. The two men were too proud to reconcile, however.

The Doctor's companion Jamie was badly injured when investigating a crashed Ice Warrior spaceship, discovered buried within the glacier, and he was rescued and taken in by Penley. Storr died trying to befriend the Martians, and Penley agreed to take Jamie to the base for medical help after meeting with the Doctor. He was able to stun the creatures when they invaded the base, by turning up the temperature and humidity.

He resumed his old role and took the decision to implement the latest action to stop the glacier, when the computer could not provide the answer - leaving Clent unable to give direction. Not only did this halt the advance, but it also destroyed the Ice Warriors and their ship.

Played by: Peter Sallis. Appearances: The Ice Warriors (1967)

• Sallis (1921 - 2017) was all set to return to the series when cast as Captain Striker in Enlightenment. Industrial action led to studio dates having to be changed, and he had to drop out - to be replaced by Keith Barron.
• Sallis will forever be associated with the role of Clegg in Last of the Summer Wine, a part he played for 37 years (295 episodes / 31 seasons). That, and as the voice of Wallace in the Wallace & Gromit animations, voicing the character in all five productions between 1989 - 2008.
• He is buried in the same rural Yorkshire churchyard as his Summer Wine co-star Bill Owen, after they had used the location for filming and fallen in love with it.
• Sallis featured in a couple of Hammer horror movies earlier in his career - Curse of the Werewolf and Taste the Blood of Dracula, the latter of which features a number of Doctor Who guest actors.