History
A Null Drive was an experimental starship drive conceived by the Dalek Time Strategist during the Last Great Time War. It was installed on the Dalek Emperor's Flagship and used during a Dalek attack on Gallifrey, for which the drive was instrumental in bypassing every defence the Time Lords had erected around their home world during the war. The Strategist described it as 'harnessing the power of the void dimension'. In practice, it allowed for a method of time travel that bypassed the vortex and conventional time travel entirely, at the expense of an astronomical energy requirement for operation. (AUDIO: Homecoming)
Functionality
Romana would detail that unlike a TARDIS that would propel itself through the time stream, the null drive would pull a vessel outside of time entirely and re-enter where directed.