The most common and most likely answer to this crossword clue is the 11 letter word CONTAINMENT
I've seen this crossword clue in The Daily Telegraph
C
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Buddy explains!
The straight part
We know that "Policy to restrict" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case policy to restrict = containment.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 CONTAINMENT mean?
CONTAINMENT noun- The state of being contained.
- The state of containing.
- Something contained.
- A policy of checking the expansion of a hostile foreign power by creating alliances with other states; especially the foreign policy strategy of the United States in the early years of the Cold War.
- A physical system designed to prevent the accidental release of radioactive or other dangerous materials from a nuclear reactor or industrial plant.
- An inclusion