Mr Blatt is described as being "a large man with a red face and a fringe of reddish hair round a shining bald spot". He wants to be the "life and soul" of any place he is in, and is of the opinion that the Jolly Roger Hotel needs brightening up. He is puzzled as to why people seem to disappear when he arrives on the scene.
Mr Blatt's car is a Sunbeam, and he also owns a boat with red sails. He smokes cigarettes, but prefers a pipe.
Mr Blatt tells Poirot that he used to sail quite a bit as a boy, off the East coast of England. He also says that he could afford a yacht if he wanted to, but he enjoys sailing in his little boat. Poirot later hears from Patrick Redfern that Mr Blatt prefers to be on his own when sailing. Poirot finds this curious, as it is unlike Mr Blatt's behaviour on land.
On the day of the murder, Mr Blatt went out sailing at 9.30 in the morning, which was what he did on most days. He tells the police that he sailed along the coast in the directon of Plymouth, and had taken his lunch with him.
It is later revealed that Mr Blatt pays income tax on a sum far more than what he could be making out of his hardware business. It is also revealed that he had some white sails for his boat, which he had stored away.
Mr Blatt turns out to be involved with drug smuggling. Colonel Weston suggests that Mr Blatt would sail to an appointed spot and be met by another boat. Mr Blatt would receive the drugs, sail to Pixy Cove, and hide them on the ledge in the cave, where someone else would pick them up.
Evil Under the Sun (1982)
In the 1982 Ustinov adaptation, the character becomes "Sir Horace Blatt". His role in the plot is slightly altered. There is no subplot of drug smuggling or the colour of sails on his boat. Here Sir Horace is a wealthy millionaire who actually knew Arlena Marshall personally and who is also a plausible suspect in her death. Some time before the events in the show, Sir Horace had been on board a ship crossing the Atlantic. He met Arlena and then proposed to her and gave her a diamond. Subsequently Arlena broke off the engagement and returned the diamond. This turned out to be a fake. Either Arlena had deliberately returned a fake diamond to him or someone had switched it without her knowing.
Knowing that Arlena would be going to the hotel island belonging to Daphne Castle, Sir Horace proceeded there in his yacht. He anchored at Ladder Bay at around the time Arlena was believed to have been killed. His fake diamond was found at the crime scene in a cave, making him a plausible suspect. Questioned by Poirot, Sir Horace admitted that he was indeed at Ladder Bay and he had come ashore to remonstrate with Arlena about the diamond but that his crew could testify that Arlena was still alive when he left. When Poirot ultimately identified Arlena's killer, he also recovered Sir Horace's real diamond and returned it to him.
Sir Horace Blatt is portrayed by actor Colin Blakely. His yacht is named the Jolly Roger, the same name as the hotel in the novel. Daphne Castle's hotel in this adaptation is not named.