Police have issued the appeal to help find William, also known as Bill, who was last seen on Monday, June 2.
A police spokesperson added: "William, 63, is 6’ tall, and believed to be wearing a black beanie hat, blue jeans and trainers.
"He is driving a blue Kia.
"William has links to Seaford, Meads and the Beachy Head area of Eastbourne.
"If you see him, please call 999 immediately quoting serial 383 of 02/06.”
1. Bill, 63
Bill, 63 Photo: Sussex Police