The most common and most likely answer to this crossword clue is the 12 letter word CHAMBERLAINS
I've seen this crossword clue in The Daily Telegraph
C
H
A
M
B
E
R
L
A
I
N
S
More clues leading to the result CHAMBERLAINS
Buddy explains!
The straight part
We know that "People close to the monarch/a couple of PMs" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case people close to the monarch/a couple of pms = chamberlains.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 CHAMBERLAINS mean?
CHAMBERLAINS noun- An officer in charge of managing the household of a sovereign, especially in the United Kingdom and in Denmark.
- A high officer of state, as currently with the papal camerlengo, but normally now a mainly honorary title.
- An upper servant of an inn.