The most common and most likely answer to this crossword clue is the 8 letter word HOUSEMEN
I've seen this crossword clue in The Daily Telegraph
H
O
U
S
E
M
E
N
More clues leading to the result HOUSEMEN
Buddy explains!

The straight part
We know that "Junior doctors" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case junior doctors = housemen.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 HOUSEMEN mean?
HOUSEMEN noun- A male follower or retainer; a male domestic worker or servant.
- A medical graduate gaining practical experience in a hospital; a house officer.