Police were called to Stanhope Road at 3am today to reports of a large-scale public order incident as Liquid and Envy closed.
Officers helped security staff from the club.
An 18-year-old man suffered a head injury and received hospital treatment.
A 21-year-old man from London has been arrested on suspicion of GBH and is in custody, and police say they are still investigating.
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Anyone with information is asked to call 101, quoting 44170109415.