series it is shown also to be capable of conventional space travel. In the 2006 Christmas special, "The Runaway Bride", the Doctor remarks that for a spaceship, the TARDIS does remarkably little flying. The ability to travel simply by fading into and out of different locations became one of the trademarks of the show, allowing for a great deal of versatility in setting and storytelling without a large expense in special effects. The distinctive accompanying sound effect – a cyclic wheezing, groaning noise – was originally created in the BBC Radiophonic Workshop by sound technician Brian Hodgson by recording on tape the sound of his mother's house key scraping up and down the strings of an old piano. Hodgson then re-recorded the sound by changing the tape speed up and down and splicing the altered sounds together. When employed in the series, the sound is usually synchronised with the flashing light on top of the police box, or the fade-in and fade-out effects of a TARDIS (see "Controls" below). Writer Patrick Ness has described the ship's distinctive dematerialisation noise as "a kind of haunted grinding sound", while the Doctor Who Magazine comic strips traditionally use the onomatopoeic phrase "vworp vworp vworp". Other appearances Television spin-offs The sound of the Doctor's TARDIS featured in the final scene of the Torchwood episode "End of Days" (2007). As Torchwood Three's hub is situated at a rift of temporal energy, the Doctor often appears on Roald Dahl Plass directly above it in order to recharge the TARDIS. In the episode, Jack Harkness hears the tell-tale sound of the engines, smiles and afterwards is nowhere to be found; the scene picks up in the cold open of the Doctor Who episode "Utopia" (2007) in which Jack runs to and holds onto the TARDIS just before it disappears. Former companion Sarah Jane Smith has a diagram of the TARDIS in her attic, as shown in The Sarah Jane Adventures episode "Invasion of the Bane" (2007). In the two-part serial The Temptation of Sarah Jane Smith (2008), Sarah Jane becomes trapped in 1951 and briefly mistakes an actual police public call box for the Doctor's TARDIS (the moment is even heralded by the Doctor's musical cue, frequently used in the revived series). It makes a full appearance in The Wedding of Sarah Jane Smith (2009), in which the Doctor briefly welcomes Sarah Jane's three adolescent companions into