[2] Campbell also appears in an episode of A Touch of Frost in series 6 as Mr Renfrew, and was the screenwriter and director of the short subject film No Deposit, No Return in 2004.

Egypt's Lost Cities, again for BBC One, was a feature-length documentary that used satellite technology to hunt for undiscovered historical treasures, and a six-part National Geographic series Time Scanners used laser scanning technology to uncover the secrets of the world's most famous historical buildings, from Machu Picchu in Peru to St Paul's Cathedral.

On BBC Four he is a regular presenter of the Horizon series, covering a wide variety of big science subjects from dogs to quantum mechanics and on the one-off documentaries Voyager: Beyond the final frontier – The story of NASA’s Voyager mission and The Drake Equation: The Search for Life – an investigation into the science and history behind our efforts to find life beyond the earth.

Dallas hosted Doctor Who's 50th Anniversary celebrations between 22 and 24 November 2013, at London's ExCel Arena, Stargazing Live, and a two-summer national tour of Bang Goes the Theory.

In October 2019, he chaired The Sky at Night: Question Time filmed at Warwick University as part of the British Science Festival.