The most common and most likely answer to this crossword clue is the 7 letter word GESTAPO
I've seen this crossword clue in The Guardian
G
E
S
T
A
P
O
More clues leading to the result GESTAPO
- Parisian is probing hole? Ring police
- Special postage for secret police
- Old police make move receiving directions to bug
- Outfit that tried to get people talking of postage fiddle
- Police try to bury dodgy tapes
- Doctored tapes buried by good old police
- Interrogators make move, receiving directions to bug
- Brutal organisation goes potty about minor strike
- . Stupidly goes round to bug police
- Set free in space with zero repressive force
Buddy explains!
The straight part
We know that "Extreme force" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case extreme force = gestapo.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.