The most common and most likely answer to this crossword clue is the 10 letter word CONDUCTORS
I've seen this crossword clue in The Daily Telegraph
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Buddy explains!

The straight part
We know that "Leaders" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case leaders = conductors.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 CONDUCTORS mean?
CONDUCTORS noun- One who conducts or leads; a guide; a director.
- A person who conducts an orchestra, choir or other music ensemble; a professional whose occupation is conducting.
- A person who takes tickets on public transportation and also helps passengers
- Something that can transmit electricity, heat, light or sound.
- An ideal of a ring that measures how far it is from being integrally closed
- A grooved sound or staff used for directing instruments, such as lithontriptic forceps; a director.
- A leader.