The character of Helen A was intended to satirise then-British Prime Minister Margaret Thatcher. Sheila Hancock stated that she "hate[d] Mrs Thatcher with a deep and venomous passion".
Sylvester McCoy told The Sunday Times in 2010 - "The idea of bringing politics into Doctor Who was deliberate, but we had to do it very quietly and certainly didn't shout about it...We were a group of politically motivated people and it seemed the right thing to do. At the time Doctor Who used satire to put political messages out there in the way they used to do in places like Czechoslovakia. Our feeling was that Margaret Thatcher was far more terrifying than any monster the Doctor had encountered. Those who wanted to see the messages saw them; others, including one producer, didn't."
The Kandyman was influenced by the mascot of Bassett's brand of Liquorice Allsorts, Bertie Bassett. But Bassett's complained about the similarity between The Kandyman and Bertie Bassett and the BBC agreed not to use The Kandyman again in another Doctor Who story.
Sylvester McCoy said that he would've begged the production team to film in black and white, as he thought the sets were lacking.
The Doctor mentions his nickname in his academy days on Gallifrey was "Theta Sigma". The Doctor's classmate Drax referred to him by this nickname in the 1979 story The Armageddon Factor.