Mark Shelmerdine, who has died aged 78 after suffering from cancer, started his career as a producer for film and TV as an accountant. An opportunity that he spotted in that role led to the production of two of the biggest TV costume series of the 1970s, Poldark and I, Claudius.

The realisation came to him while working as financial director of the Taylor Clark group, run by the Scottish businessman Robert Clark, whose assets included the dormant London Films, founded in 1932 by the Hungarian-born British film-maker Alexander Korda.

Shelmerdine not only saw the potential to exploit London Films’ back catalogue of titles, but also unearthed contracts that had given the company unused screen rights to literary classics. These included Winston Graham’s romantic Poldark novels, set in 18th-century Cornwall, and he arrived at a co-production agreement with the BBC.

The result was the Sunday-evening period drama Poldark, which ran for two series (1975-77) with tales of skulduggery, smuggling and tin-mining. It also brought heart-throb status to Robin Ellis as the dashing squire Ross Poldark, returning from fighting in the American War of Independence and eventually marrying Angharad Rees as Demelza Carne – and revenue from sales to more than 40 countries.

From the same London Films source Shelmerdine also came across I, Claudius, a blood-letting, taboo-busting tale of the early Roman empire which was adapted from novels by Robert Graves for the BBC by Jack Pulman and starred Derek Jacobi as emperor Claudius. Negotiations with the BBC were rather more protracted than they had been with Poldark, but the series finally arrived on TV screens in 1976, and it won an Emmy and three Bafta awards.

This led to further co-productions with the BBC when Shelmerdine bought the rights for serialisations of Testament of Youth (1979), based on Vera Brittain’s first world war memoir, and Thérèse Raquin (1980), from Émile Zola’s novel.

In each case London Films held on to the distribution rights, and eventually Shelmerdine saw the potential for reviving the firm as a production company. He persuaded Clark to sell him the business and subsequently became an executive producer on The Scarlet Pimpernel (1982), with Anthony Andrews and Jane Seymour in a TV movie remake of a 1934 production that had been directed by Korda.

Branching out from the London Films catalogue – and pioneering co-production with both British and foreign companies – Shelmerdine then made the mini-series Little Gloria ... Happy at Last (1982), starring Lucy Gutteridge as the American socialite Gloria Vanderbilt, and the TV movies The Country Girls (1983), based on Edna O’Brien’s acclaimed book, and Kim (1984), from Rudyard Kipling’s novel, with Peter O’Toole as the Tibetan lama.

In 1980 Shelmerdine was one of those who set up the Independent Programme Producers’ Association to negotiate with Channel 4, due to start broadcasting two years later and launched as a commissioner rather than a production company. The association helped to shape the independent sector.

Shelmerdine was born in Fulmer, Buckinghamshire, during the last months of the second world war to Margaret (nee Bedwell), an army nurse, and Dick Shelmerdine, who was serving in the Highland Light Infantry. The family moved to Singapore, where his father served in the police before becoming commissioner of police in the Bahamas, although Shelmerdine was by then attending a Devon prep school. He went on to Blundell’s school in Tiverton and trained as a chartered accountant at Coopers & Lybrand, qualifying in 1968.

After joining the Taylor Clark group, he found himself charged with compiling weekly box-office reports for two other Clark-owned businesses, Caledonian Associated Cinemas and the ABC chain, analysing which films attracted the biggest audiences. He then turned his attention to London Films, which had put out movies such as The Private Life of Henry VIII (1933), The Thief of Bagdad (1940) and The Third Man (1949), but had effectively ceased activity after Korda’s death in 1956. I, Claudius had actually been put into production by London Films in 1937, with Charles Laughton in the title role, but had been abandoned after Merle Oberon, playing Messalina, was injured in a car crash.

As executive producer with London Films, Shelmerdine was also responsible for The Old Men at the Zoo (1983), Troy Kennedy Martin’s five-part adaptation for the BBC of Angus Wilson’s novel, updated as a satire on the Margaret Thatcher era. In a different vein, Shelmerdine and London Films co-produced, with the American CBS network, the 1985-89 revival of the sci-fi anthology series The Twilight Zone.

His other business ventures included setting up SelecTV, a pioneer in the cable television and pay-per-view market, in 1980, and, after moving to the US five years later, co-founding Bafta’s Los Angeles branch. This came after his marriage in 1985 to the self-help author Susan Jeffers, with whom he set up a publishing company, Jeffers Press. The following year he sold the Korda catalogue to the ITV company Central Television.

Shelmerdine’s first marriage, to Anne Eastwick in 1967, ended in divorce. Jeffers died in 2012 and two years later he married Donna Luskin, who survives him, along with Guy and Alice, the children of his first marriage.

• Mark Edward Alexander Shelmerdine, television and film producer, born 27 March 1945; died 26 October 2023