Now highly prized by collectors, Hockney's billboard art included stunning silk-screen images such as the harlequin for a production of Parade and the childlike trio of faces for Igor Stravinsky, both performed at the Metropolitan Opera, New York, in 1981, which made pounds 5,750 and pounds 3,450 respectively. Others were made to promote exhibitions of his original work in New York, Los Angeles, Australia, Tokyo, Honolulu, Tel Aviv - and the artist's home town of Bradford, West Yorkshire.
Mr Baggott, 53, of Fulham, west London, who has known David Hockney since the late Sixties, said: "It's a stunning result. I was lucky because I loved what I was collecting and I was in the right place at the right time."
Hockney has always been passionately interested in music and theatre, and there is an inter-relationship between his paintings and theatre design. The artist has also provided the designs for major opera productions around the world.
Other highlights of the sale included Hockney's 1966 poster for the Royal Court production of Ubu Roi, with Max Wall, which realised pounds 2,530, and a 1989 poster for a Frankfurt gallery promoting recent paintings, which made pounds 1,840. A 1988 retrospective, featuring a dog curled up asleep, went for pounds 1,380.
Christie's specialist Nicolette White said: "It's a fantastic result - worldwide interest in this unique single-owner collection has meant a sale with 100 per cent of the lots sold."
Mr Baggott said: "I had known David Hockney from the late Sixties but could never afford anything original. While on a visit to America in the early Seventies I saw a poster of his in a shop window but it was $20 and more than I could afford.
"By coincidence, someone bought me that poster as a Christmas present and it set me on the path to collecting Hockney posters and catalogues."
As the collection burgeoned, Mr Baggott found he had posters that even Hockney did not know existed. "Posters were being produced without the artist's knowledge and in breach of copyright. I used to pop into David's office and tell them about posters I had acquired and in return they would give me some others," he said.
Ms White said: "When Hockney staged exhibitions of his original artwork he usually produced posters to advertise them. As a result, it is possible to visually trace his prolific career solely through his posters.
"One reason for their popularity is that they fit perfectly into the modern interior and often appear decorating living space on film and television sets, including [television] productions such as This Life and Absolutely Fabulous.
"The production of these David Hockney posters is strictly controlled to maintain their quality. Hockney's studio is often involved in the format and design of lettering for the posters. Many are also countersigned by Hockney, which increases their desirability and hence value.
"Occasionally more than one poster was produced for the same exhibition so it is difficult to state exactly how many Hockney posters are in existence."
She added that there was one "unrivalled" private collection of Hockney posters which had been "avidly amassed" since the Seventies. Yesterday, that collection's former owner was almost pounds 100,000 better off.