Labour leader Jeremy Corbyn was hit by an egg during a visit to a mosque on Sunday.
Scotland Yard said that a 41-year-old man had been arrested over the egg throwing incident on Seven Sisters Road, north London.
The man was "quickly detained", according to a police statement.
Mr Corbyn, whose Labour Party announced this week that it would back a second referendum on Brexit, was not harmed during the incident.
The visit was to mark Visit My Mosque Day