Luke Parsons (TV: The Christmas Invasion) was an Intelligence Officer (PROSE: The Time Traveller's Almanac [+]Loading...{"chaptname":"Everything Changes","page":"82","chaptnum":"3","1":"The Time Traveller's Almanac (reference book)"}) working for UNIT underneath the Tower of London. He was hypnotised by the Sycorax using blood control as he was A positive. His blood record on the UNIT medical record files was used to identify the common factor between the hypnotised people. After the Tenth Doctor disabled the device he returned to normal. (TV: The Christmas Invasion)