Energy weapon

The energy weapon was a mounted alien item of heavy artillery used to cause mass destruction with a single shot. In 2007 during the Sycorax's appearance over London on Christmas day, the Torchwood Institute utilising the energy weapon from the Jathaa sunglider shot down the Sycorax's craft under the orders of Harriet Jones. (DW: The Christmas Invasion).

The shots were fired in four parts before meeting to form one huge blast. After the battle of Canary Wharf, the weapon was presumably scavenged and built onto the airship carrier Valiant. UNIT used it to blow up part of the Atmos factory during the Sontaran invasion of Earth in 2009. (DW: The Poison Sky)

It is as yet unknown if the weapon was added after the fall of the Master or if Harold Saxon himself incorporated it into the design. The weapon was most likely lost when the Daleks attacked and destroyed the Valiant during the war in the Medusa Cascade. (DW: The Stolen Earth)