The Monster of Peladon is the fourth serial of the 11th season of the British science fiction television series Doctor Who, which was first broadcast in six weekly parts on BBC1 from 23 March to 27 April 1974.
In the serial, the engineer Eckersley (Donald Gee) and the rogue Ice Warrior Commander Azaxyr (Alan Bennion) conspire to take over the planet and sell its minerals to Peladon's enemies in Galaxy Five.
This threatens to slow trisilicate supplies even further, so Engineer Eckersley, a human in charge of the refinery, coaxes Alpha Centauri to send for Federation troops to help restore order.
There is now a realignment in Pel politics: Ortron and Gebek join forces in seeking to rid the planet of the Ice Warriors.
The Ice Warriors now impose martial law on the capital, imprisoning the Queen and her courtiers, and even killing Ortron when he tries to flee.
The truth is now revealed: Azaxyr and Eckersley are both Galaxy Five agents and have engineered the crisis and occupation as a means to control the trisilicate supply.
The mineral was named Trisilicate because Barry Letts saw it listed on the back of a tube of Boots toothpaste as one of the ingredients.
While he noted that story had its moments, he criticised the casting and felt that Pertwee and Sladen continued to lack rapport.
[6] John Sinnott in DVD Talk gave the serial three out of five stars, feeling that the shift in tone halfway through kept interest while the plot was similar and the subplots were repetitive.