Kate Lethbridge-Stewart

Played by Jemma Redgrave

"Science leads, he always told me. Said he'd learned that from an old friend"

Kate Lethbridge-Stewart is the commander-in-chief of the Unified Intelligence Taskforce. She also happens to be the daughter of the late, esteemed Brigadier Alistair Gordon Lethbridge-Stewart, the long-time friend and colleague of the Doctor.

Practical, disciplined and determined, she is a firm believer that science leads over a more traditional military response when the Earth is under attack. She used psychic paper to summon the Doctor when the mysterious Shakri cubes arrived in the night.

If the situation arises, Kate won’t flinch from taking painful decisions. When a Zygon invasion had reached the secret UNIT base under the Tower of London, rather than allow the collection of alien weaponry to fall under the control of the Zygons, Kate threatened to self-destruct the entire Black Archive, destroying London in the process. Thankfully, the Doctor was able to prevent this from happening!

She regularly finds herself in the line of fire; when the presidential plane Boat One came under attack from Cybermen in mid-air, Kate was sucked out. Fortunately her father, who had been converted into a Cyberman, was able to fly up into the sky and save her.

It was Kate's intelligence and strategic senses that made her realise the infiltration and control of UNIT by a disguised Grand Serpent in 2017, managing to avoid an assassination attempt and going underground to lead the resistance against the Sontarans. It was in the heat of this invasion that she was finally able to meet the Thirteenth Doctor for the first time.