Britain has a long tradition of producing fine science fiction, and while searching for an intact online copy of the excellent "Quatermass and the Pit" (known to us Yankee rebel dogs as "Five Million Years To Earth") I ran across this terrific and evergreen (pun intended) example of the genre from Security Pictures Ltd. which, as far as I can tell, came into existence to produce just this one film before vanishing forever.
What more needs be said about "The Day of the Triffids " than...giant killer walking plants from space!
Sure the ending is a little weak but, hey, giant killer walking plants from space!
Enjoy.