Are you...
3 seconds sound clip from the Chitty Chitty Bang Bang (1968) movie soundboard.
You can hear this line at 02:19:51 in the Blu-ray version of the movie.
Quote context
[...]
- Look, that's Lord Scrumptious' car.
- I wonder what it's doing here.
- Boom! Boom! Boom! That's wiped out your dashed cavalry.
- Yes, sir. But I have my 2nd lnfantry battalion attacking here from the rear.
- Attacking from the rear? That's dashed unethical.
- Artillery, prepare to open fire. Fire!
[...]