Jill Lanchaster
From Tardis Wiki, the free Doctor Who reference
Jill Lanchaster was a Vardan who posed as the daughter of Professor Lanchaster in June 1964. She couldn't remember how her "father" was attacked. She went shopping with Romana II as a distraction. Romana realised that she wasn't human when she got a headache. Jill then started the invasion by making sure that the equipment that led them to Earth was attached to the NATO security systems. She was cancelled out when Romana and K9 Mark II broadcast a cancellation wave. (AUDIO: Wave of Destruction)