L is for... Lexa

Lexa was High Priestess of the Deons - a religious sect from the planet Tigella. Tigellan society was split between the Deons and the science-rationalist Savants, with a neutral elder named Zastor acting as mediator and leader. Many years before, a strange object had fallen into the jungles of the planet - a 12-sided power source known as the Dodecahedron. The Deons believed that this had been sent by their god Ti, whilst the Savants suspected a more secular origin. The Dodecahedron was harnessed, and its energy powered their subterranean city.

When the Dodecahedron began to fail, putting the city at risk, Zastor called upon the Doctor to come and help. He had visited the planet in the past. Lexa was angry at this, and only agreed if the Doctor swore allegiance to Ti before he would be permitted to enter the inner sanctum where the object was housed.

The Doctor became trapped in a time loop with Romana and K9, and his place was taken by the alien Meglos - last of the Zolfa-Thuran race who were the original owners of the Dodecahedron. It powered a vast energy weapon, and he wanted it back. Meglos stole it by shrinking it, and when the Doctor finally arrived he found himself arrested by Lexa and her people, who sentenced him to be sacrificed to Ti.

When she discovered the truth, Lexa decided to help. She sacrificed herself to save Romana when she was fired upon by Gaztak mercenaries.

Played by: Jacqueline Hill. Appearances: Meglos (1981).

• Hill had previously portrayed Barbara Wright, companion to the First Doctor in Seasons 1 and 2.
• She had given up work to concentrate on raising a family and had only recently returned to acting.
• Oddly, when director Graeme Harper wished to cast Michael Craze (who had played companion Ben) in The Caves of Androzani he was told by John Nathan Turner that companion actors could not be brought back as different characters.