The most common and most likely answer to this crossword clue is the 7 plus 7 letter word ENGLISH CHANNEL
I've seen this crossword clue in The Guardian
E
N
G
L
I
S
H
C
H
A
N
N
E
L
More clues leading to the result ENGLISH CHANNEL
- Exploding shell enhancing D-Day landers’ first obstacle?
- All in Schengen angry about Hungary’s barrier to migrants?
- Shipping area that’s not included in Scottish TV?
- Arm of Atlantic that’s familiar to Brits surfing?
- Something viewed by many here as what divides us from Europe
- 4 Educt two sections between UK and France
- Discovery, perhaps, of part of Atlantic Ocean
- Busy shipping lane gets language access
Buddy explains!
The straight part
We know that "barrier to migrants" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case barrier to migrants = english channel.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.