The most common and most likely answer to this crossword clue is the 6 plus 4 letter word MINUTE HAND
I've seen this crossword clue in The Daily Telegraph
M
I
N
U
T
E
H
A
N
D
More clues leading to the result MINUTE HAND
Buddy explains!
The straight part
We know that "one keeping going round the clock?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one keeping going round the clock? = minute hand.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.