The most common and most likely answer to this crossword clue is the 6 letter word SEWERS
I've seen this crossword clue in The Daily Telegraph
S
E
W
E
R
S
Buddy explains!
The straight part
We know that "People dealing with needles/channels" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case people dealing with needles/channels = sewers.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 SEWERS mean?
SEWERS noun- A pipe or system of pipes used to remove human waste and to provide drainage.
- A servant attending at a meal who is responsible for seating arrangements, serving dishes, etc.
- One who sews.
- A small tortricid moth, the larva of which sews together the edges of a leaf using silk.