They include extremely rare hoarding-size posters of the "Careless Talk Costs Lives" cartoon series, which featured people confiding to each other unaware that Hitler was concealed nearby; in the wallpaper, under a table, in a painting, or at an open window.
Proofs of the series by the cartoonist Kenneth Bird - who worked under the nom de plume Fougasse - and many other famous war posters exhorting civilians to dig for victory, women to work in factories, housewives to save old bones and parents to evacuate children, are included in the sale at Onslows on 2 March.
The Fougasse posters are estimated to be worth between £400 and £700 each, and the 80 or so general propaganda posters are expected to sell for between £30 and £200 each. Mr Embleton, now 87, began his collection in 1939 when he was seconded from his job as art director at Odham's, a publishing firm, to the Ministry of Information in Gower Street, central London.
"I wandered up there the morning war was declared and sat there wondering what to do," he recalled yesterday. "It was very difficult to suddenly become a civil servant - all the policy had to come from Downing Street and one couldn't get on very fast."
The newly-headhunted art director was the man who more than any other shaped British war propaganda, running an internal advertising agency at the Ministry of Information.
"I was responsible for spending millions of pounds of Treasury money. I started with three artists and I finished off with 70," he said. "It was wonderful. I was 32 then, too old to be called up, but full of energy. I sent my wife and daughter to Cornwall, worked 12 hours a day and slept in the ministry cellars." His favourite posters are the ones best known today, warning against careless talk.
He said: "Downing Street decided to have the posters early on, so I rang Fougasse and told him we had to show people the importance of keeping their mouths shut because Goebbels had a network of spies.
"They were a series of eight. We printed two-and-a-half million and they were praised to heaven. I felt they struck the right note to the man in the street. The British character is such that even in the direst situation, we have got a sense of humour." Mr Embleton has kept them in the spare bedroom of his East Sussex cottage for years, but is not sorry to lose them. He said: "I'm now 87. There's no point in just hanging on to them, so I'm prepared to let them go to what I hope will be good homes."