[EvilCapitalist]

That’s the one.

[oldvirginian]

“That’s the one.”

I looked it up, the episode was Aliens of London.
https://tardis.fandom.com/wiki/Aliens_of_London_(TV_story)

The backbencher was Harriet Jones. The aliens were the Slitheen family. Also the first time UNIT was involved.
Chris Eccleston was the Doctor.