But Torchwood appears in Doctor Who.
Season two of Doctor Who was all about "What is Torchwood?"
Almost every episode, had some sly remark or off the cuff negative space stuff about a secret spy agency that was/is hunting aliens humorously just beyond Doctor Who's earshot and... But that would be telling.
Of course that was evil Torchwood before the Doctors friend took over, well actually there were 5 Torchwoods and... That would be also telling.
If it saves time, Torchwood is just a remake of Captain Scarlet.
"Torchwood" is an anagram of "Doctor who"
In the real world, because of the secrecy of bringing back Doctor Who from the dead in 2004ish, "Torchwood" was the code name they used for Doctor who for production/bookkeeping purposes to keep the monkeys and the press in the dark about what was really happening.