Travellers gripping newcomers outside a pub (12)

I believe the answer is:

straphangers

I'm a little stuck... Click here to teach me more about this clue!

'travellers' is the definition.
(straphanger is a kind of traveller)

'gripping newcomers outside a pub' is the wordplay.
I cannot quite see how this works, but
'a' could be 'an' and 'an' is found within the answer.
'pub' could be 'ph' (abbreviation) and 'ph' is found in the answer.
This may be the basis of the clue (or it may be nonsense).

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I've seen this clue in The Times and The Sunday Times.

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