The most common and most likely answer to this crossword clue is the 6 letter word REDCAP
I've seen this crossword clue in The Times
R
E
D
C
A
P
More clues leading to the result REDCAP
- Military policeman in preferred capacity
- MP backed horse securing lead in Derby
- MP died during summing up
- Example of MP inflamed over EU farming system?
- MPgets better
- Policeman
- Policeman on duty, initially covering
- Left-winger to outdo as MP
- One in military police, 14, going across
- Bird is embarrassed on top
Buddy explains!

The straight part
We know that "Military policeman" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case military policeman = redcap.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.
What does REDCAP mean?
REDCAP noun- A member of the Royal Military Police a unit in the British army.
- A porter in a US railway station.
- The European goldfinch (Carduelis carduelis).
- A type of evil goblin or imp.
- A breed of poultry.