1968 (production)

January

 * January - Terrance Dicks was hired to the Doctor Who production team, as an assistant for Derrick Sherwin.

March

 * 29 March - The decision was made to reduce The Dominators from six parts into five.

April

 * 19 April - The Mind Robber was extended from four parts into five, with Sherwin commissioned to write a new opening episode for the story.

June

 * 21 June - Episode one of The Mind Robber was recorded at BBC Television Centre Studio 3. (TCH 13)
 * 28 June - Episode two of The Mind Robber was recorded at BBC Television Centre Studio 3. (TCH 13) Frazer Hines was absent from this filming session due to being ill with chicken pox and Hamish Wilson temporarily stepped in as Jamie. (DCOM: The Fact of Fiction)

July

 * 5 July - Episode three of The Mind Robber was recorded at Lime Grove Studios D. (TCH 13)
 * 12 July - Episode four of The Mind Robber was recorded at Lime Grove Studios D. (TCH 13)
 * 19 July - Episode five of The Mind Robber was recorded at BBC Television Centre Studio 3. (TCH 13)

September

 * 20 September - Episode one of The Invasion was recorded at Lime Grove Studios D. (TCH 13)
 * 27 September - Episode three of The Invasion was recorded at Lime Grove Studios D. (TCH 13)

October

 * 4 October - Episode three of The Invasion was recorded at Lime Grove Studios D. (TCH 13)
 * 11 October - Episode four of The Invasion was recorded at Lime Grove Studios D. (TCH 13)
 * 18 October - Episode five of The Invasion was recorded at Lime Grove Studios D. (TCH 13)