Season 7 The seventh season of " Doctor Who " ran between 3 January 1970 and 20 June 1970 . The debut series of Jon Pertwee as the Third Doctor , it was the first series produced and broadcast in colour and the first set entirely in one time period and almost entirely on Earth . Although the series did not have an overall story arc , it did feature a recurring subplot of the Doctor trying to adjust to life as an exile while trying to circumvent the restrictions placed upon him by the Time Lord s . Beginning with this series and continuing for the next few years , most storylines involve the Doctor working with UNIT . It consisted of four serials and twenty - five episodes . It was the shortest series of " Doctor Who " to date ( and had the fewest number of serials until Season 23 ) . It has the distinction of being the earliest " Doctor Who " series to exist in its entirety ( though not completely in colour , with the monochromatic copies of episodes later subjected to various recolourisation techniques ) in the BBC archives . This is also the first series ( other than the first one ) to not feature any returning monsters from earlier stories . Beginning with this series and continuing through the Pertwee era , the BBC changed the show ' s scheduling with new , shorter series from this point beginning in either January or very late December , rather than Autumn as had been the previous format ; the series would return to an Autumn series start in the Tom Baker era . The new scheduling reflected the change from around forty to forty - five episodes a series to more or less twenty - six per series , though the length of the episodes remained the same . Production - wise , this season was a rather prominent transitionary period for the show , accentuated by a year - long hiatus following the conclusion of " The War Games " . With the 1960 ' s coming to a close , this season saw the last two stories to be filmed during the decade : " Spearhead from Space " and " Doctor Who and the Silurians " , both of which were filmed in late 1969 . Additionally , as mentioned before , the series made the leap from monochrome to full - colour , crossing paths with the arrival of Jon Pertwee as the Third Doctor . Having done away with the entire main cast at the end of the previous season , Season 7 also built up a new team for the Doctor , consisting of Brigadier Lethbridge - Stewart & Sergeant Benton ( both of whom had already been introduced in " The Web of Fear " and " The Invasion " respectively ) and Dr . Elizabeth Shaw . This also saw the only time in the classic series where there was no defined producer for a time , with Barry Letts only taking up the role midway through production of " Doctor Who and the Silurians " . With the show amassing a considerably larger budget this season , Letts gave the show many technological achievements that came with its new colour presentation , most notably Colour - Separation Overlay , and stories began to feature a greater amount of on - location filming and action sequences than before . Overall , the seventh season marked the departure of several staples of the 1960s seasons , while introducing many more elements that would become prevalent for the rest of " Doctor Who " ' s run . Adaptations and merchandising . Home media . Download / streaming availability . BritBox is available only in the US . iTunes stores carry " Doctor Who " serials in Australia , Canada , France , Germany , the UK and US . External links . BBC website guide to Series 7