1. By exchanging laser fire with Mr Smith, K-9 provides Sarah Jane with the distraction she needs to download the Armageddon Virus into Mr Smith. After this fight, K-9 returns to the black hole. In the finale of Doctor Who Series 4, "Journey's End", Sarah Jane calls on K-9 to leave the black hole again to transmit the TARDIS base code to Mr Smith so that the latter can access its navigation system and direct the TARDIS back to the solar system whilst towing the Earth home. In Series 3, K-9 permanently leaves the black hole because Eve's ship needed to use the black hole's energy, thus closing it. K-9 departs the Smith home again in "The Nightmare Man", when Sarah Jane sends him off to be Luke's companion at Oxford University. L Carla Langer Carla Langer, played Jocelyn Jee Esien, is the mother of Clyde Langer (Daniel Anthony). She is mentioned throughout the first and second series before making her debut in the second series serial The Mark of the Berserker. Prior to the programme, she and Clyde lived in Hounslow before moving to Ealing after her ex-husband and Clyde's father, Paul Langer, left them and went to live in Germany with Carla's sister, Melba. She subsequently appears in The Empty Planet and The Curse of Clyde Langer. During the Dalek invasion of Earth in the Doctor Who episodes "The Stolen Earth" and "Journey's End", she and Clyde took shelter together. Lesley Lesley, played by Rungano Nyoni, was Mrs Wormwood's PA and Secretary at Bubble Shock! as seen in "Invasion of the Bane". Although not seen in Bane form, as with the rest of the factory workers, it was implied she was a Bane. She was tasked with killing Sarah Jane Smith in a lift. However, Sarah spotted her in a mirror and intercepted the attack, wounding Lesley. Brigadier Sir Alistair Gordon Lethbridge-Stewart Retired UNIT commanding officer and Sarah Jane's friend since 1973, Brigadier Sir Alistair Gordon Lethbridge-Stewart is shown in a photograph in Sarah Jane's attic in the pilot episode, "Invasion of the Bane". He returns in-person in "Enemy of the Bane", having been a frequent companion of the Doctor on Doctor Who from The Web of Fear through Battlefield and the (arguably non-canonical) special "Dimensions in Time". He co-stars with Sarah Jane and fellow former companion Victoria Waterfield in the direct-to-video movie, Downtime. In addition to his