The most common and most likely answer to this crossword clue is the 5 plus 5 letter word KINGS CROSS
I've seen this crossword clue in The Times
K
I
N
G
S
C
R
O
S
S
More clues leading to the result KINGS CROSS
- Maybe Henry VIII is displeased — it's the end of the line for some
- Sings and rocks out somewhere in London
- Monarch’s annoyed in 11
- Monarch is furious with part of London
- “End of the line” letter on valentine’s card to Mrs Simpson?
- Cards put out where lines end
- Book on bridge in part of London
- Powerful men meet leaving station
Buddy explains!
The straight part
We know that "it's the end of the line for some" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case it's the end of the line for some = kings cross.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.