The 76-year-old victim was at the Gardeners Arms pub in Selsfield Road, Ardingly, at 9pm on Thursday August 15 when a man approached him, criticised him and began pointing at the victim’s face.
When the victim tried to walk away the man threw a pint of beer at him.
PC Grant Jones said: “The photograph shows a man in a black jacket who we would like to speak to about the incident.
“I’m also keen to speak to anyone else who was in the Gardeners Arms on 15 August and who saw the drink being thrown or the events leading up to it. They may have only seen or heard part of what happened but we would still like to speak to them as soon as we can.”
Anyone with information should call 101 quoting serial 776 of 16 August or the independent charity Crimestoppers anonymously on 0800 555111.