A 41-year-old man from France is being questioned after "what appears to be a firearm" was discovered in a bin at Gatwick airport, Sussex Police said.
The airport's North Terminal was evacuated following a subsequent security alert, but has now been re-opened.
Gatwick Airport's North Terminal has reportedly been evacuated.
It comes amid heightened security following a series of deadly terror attacks in Paris.
Gatwick Airport representatives were not immediately available for comment.
Connor Gillies, a reporter for Capital FM, tweeted a picture showing floods of people making their way outside the terminal.
The Democratic presidential candidate may also have shown his cards on his choice of running mate.
The US president also shared a post on Twitter accusing Dr Anthony Fauci of misleading the public over hydroxychloroquine.
Fears over an impending second wave of coronavirus dominates Wednesday’s front pages.