Wrongly believed hotel is obliged to put on film (10)

I believe the answer is:

misthought

'wrongly believed' is the definition.

'hotel is obliged to put on film' is the wordplay.
'hotel' becomes 'h' (phonetic alphabet: alpha, bravo, charlie etc.).
'is obliged to' becomes 'ought'.
'put on' says to put letters next to each other.
'film' becomes 'mist' (I've seen this before**).
'h'+'ought'='hought'
'hought' after 'mist' is 'MISTHOUGHT'.

I've seen this clue in The Times.

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