Jathaa sunglider laser

The Jathaa sunglider laser was the primary laser weapon of a Jathaa sunglider.

Overview
The weapon worked by five energy beams converging together to form one larger beam. This single larger beam was used to destroy a target. (TV: The Christmas Invasion, The Poison Sky)

On a Jathaa sunglider, all the components of the weapon were mounted on a platform attached to the bottom of the ship. (TV: End of Days) The version of the weapon on the Valiant utilised a similar configuration. (TV: The Poison Sky) The version utilised by Torchwood One had the five smaller laser beams situated at five different points around London. (TV: The Christmas Invasion)

The size of the blast emitted by the laser was adjustable. A small-scale blast fired at close-range was able to blast open the doors of the ATMOS factory with minimal damage to the structure otherwise (TV: The Poison Sky) while a larger-scale blast fired from Earth into space was able to effortlessly destroy the Sycorax spaceship. (TV: The Christmas Invasion)

History
In 1997, Torchwood managed to shoot down a Jathaa sunglider. Over the next ten years, Torchwood was able to reverse-engineer the sunglider's laser weapon for their own use to defend the Earth. (TV: Army of Ghosts)

In 2006, during the Sycorax invasion of Earth, Torchwood prepared the laser on Prime Minister Harriet Jones' order. During the invasion, Torchwood was initially hindered in their efforts to prepare the laser as one-third of their staff was under the Sycorax blood control. Though the Sycorax spaceship was retreating, Harriet gave the order to fire. The laser destroyed the retreating Sycorax ship in space, effectively shooting the ship in the back. Enraged by Harriet's actions, the Tenth Doctor orchestrated her downfall. (TV: The Christmas Invasion) After the Doctor came to Torchwood One, Yvonne Hartman explained Torchwood's role in the events and their acquisition and use of the weapon. (TV: Army of Ghosts)

At some point, a smaller version of the laser was fitted onto the Valiant. While retaking the ATMOS factory during the Sontaran invasion of Earth, Colonel Mace had the Valiant use its laser to blast open the factory doors. The explosion it created also killed several Sontarans. (TV: The Poison Sky)