The most common and most likely answer to this crossword clue is the 8 plus 6 letter word STAMPING GROUND
I've seen this crossword clue in The Daily Telegraph
S
T
A
M
P
I
N
G
G
R
O
U
N
D
More clues leading to the result STAMPING GROUND
- Reason to support marking familiar territory
- Patch up gang in storm that’s dispersed and died
- Territory shown by map sadly secured by fraud and crushed
- A politician caught in trap set in the constituency
- Politician involved in smear goes to earth in usual hangout
- Putting one’s foot down developing drug on familiar territory
- Covert scheme involving a politician broke up favourite spot
Buddy explains!
The straight part
We know that "familiar territory" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case familiar territory = stamping ground.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.