The most common and most likely answer to this crossword clue is the 9 letter word CALLAGHAN
I've seen this crossword clue in The Guardian
C
A
L
L
A
G
H
A
N
More clues leading to the result CALLAGHAN
- PM to ring Kabul warlord perhaps forsaking force
- PM‘s silver ring and Chinese dresses
- Visit a country in Africa that lacks a prime minister
- PM‘s instruction to contact man in Kabul, fellow having disappeared
- PM to phone Turkish leader before start of negotiations
- Labour leader making a change, mostly wrong about everything
Buddy explains!
The straight part
We know that "Labour leader" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case labour leader = callaghan.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.