[1] Baker had previously declined to feature in any Big Finish releases, but after recording a trilogy of full cast audio boxsets for BBC Audiobooks, he decided to participate.
A fifth series of adventures was released from January 2016, this time featuring Lalla Ward as the second incarnation of Romana and John Leeson as K9.
An eighth series was released from January 2019, featuring John Leeson as K9 and a new companion WPC Ann Kelso played by Jane Slavin.
A ninth series was released from January 2020, featuring Lalla Ward as Romana II, John Leeson as K9 and Matthew Waterhouse as Adric.
A special, featuring Louise Jameson as Leela and John Leeson as K9 was released in May 2020, which is set between the stories Underworld and The Invasion of Time.
A thirteenth series was released from March 2024 in three volumes, featuring Christopher Naylor as Harry Sullivan and Eleanor Crooks as Naomi Cross.
Senior Producer John Ainsworth said: “Long-term listeners will know that we record Tom Baker's Fourth Doctor Adventures well in advance, but there might be some surprises on the way.