Episode title question

I was recently watching the More than 30 years in the TARDIS special, and they showed a clip of an episode in black and white where a companion finds a corpse in an elevator. The body is covered in cobwebs and falls over when touched. Does anyone know the episode this is from? Thank you.

I think the clip you've seen is "The Web of Fear" where they find the man covered in webbing.  He's behind or next to a sliding metal gate as is often used in elevators, or in this at the top of the steps leading out of the Tube to the surface of London.

Not sure if this is from Episode 1, a censor clip from the other episodes, or a "recreated" scene done especially for "30 Year on the TARDIS".