A 40-hour stand off involving a 72-year-old man old man refusing to leave his house in Pagham, near Bognor Regis, ended safely just after 8.45am.
Armed police surrounded the property in Harbour Road, after receiving reports at around 4.10pm on Sunday that the pensioner had a gun and was using threatening behaviour.
Ambulance and fire services were called forward on Tuesday morning as the man threatened to set fire to the house, but at 8.42am he told police that he was leaving the property and a few minutes later, he left, closing the door behind him.
He was arrested on suspicion of threats to kill and possession of a firearm with intent to endanger life.
"This was a long, complex and challenging negotiation, but I am delighted to say that it has ended peacefully and safely as this was always our absolute priority. I also pay tribute to all the police officers and staff involved for their professionalism and determination to resolve this safely."