During the Last Great Time War, the Time Lords deduced that the Daleks had derived their time technology from their own and so their technical division postulated that it may be possible to retroactively insert a "Trojan Horse" program into dematerialisation circuits at a time period prior to the Daleks' acquisition of the technology, thus giving the Time Lords a shut-down option that would deprive the Daleks of time travel capability. Whilst the War Council agreed that it would be an effective defense, the possibility was recognised that the Daleks could discover such a program and potentially use it against the Time Lords. A subcommittee looked into the ramifications of this course of action and was to report back once its findings had been analysed. (PROSE: Dalek Combat Training Manual)