The most common and most likely answer to this crossword clue is the 5 plus 9 letter word CHARM OFFENSIVE
I've seen this crossword clue in The Daily Telegraph
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More clues leading to the result CHARM OFFENSIVE
- Carbon damage, very displeasing for PR campaign
- Manipulating tactic, something attractive and repulsive
- Conservative hurt by insulting campaign to win support
- Slough’s allure is, on reflection, very English
- Damage after Conservative goes on disagreeable mission to gain favour
- Talisman joins odious campaign of flattery
- Thing I like about much of East Anglia I have summarised, bringing flattery to an end?
- Attempt to get one’s own way with nasty trinket first
- Forced march — campaign will flatter to deceive
- A PR campaign could start attack after attack
Buddy explains!
The straight part
We know that "mission to gain favour" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case mission to gain favour = charm offensive.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.