60s/70s UK Sci Fi Film

[ststfn]

I remember seeing this film on TV, when I was a kid in early 70's, so probably puts this in late 60's category.  I remember english accents, and evil spys or scientists. Strongest memory is of characters being sprayed in the face with some aerosol gas to render them unconscious.  Any ideas ?

[Fat Jenkins]

Was it black and white or color?

I want to say the flick "Carry On Spying" was about aerosol knockout spray or it might have been death spray.

Otherwise I'd say read through the spoilers for "Dr. No", "From Russia With Love", or perhaps another Bond flicks. They always had the coolest gadgets, and I'd bet you'll find your sleep spray devices.

[Newt]

Could it have been an episode of the first series of The Avengers?  The knock out spray rings a bell there.