A photographer submitted a photo of a search and rescue helicopter to this newspaper at about 3.30pm.
There were then reports on social media of an emergency incident at Aldwick.
An HM Coastguard spokesperson said at 5pm: “HM Coastguard has been responding to reports of a missing person in the Aldwick area, West Sussex. Coastguard Rescue Teams (CRTs) from Hayling Island, Selsey and Littlehampton were sent to assist in the search, alongside Sussex Police, an HM Coastguard Rescue Helicopter and RNLI lifeboats from Bembridge, Littlehampton and Selsey. The search was stood down at 5pm with nothing found.”

1. Bognor
There have been reports of HM Coastguard attending an incident near Bognor this afternoon (Sunday, September 29) Photo: Sussex News and Pictures