The client places a bet that so-and-so will live until a certain date, and he bets against them at extortionate odds, collecting the winnings when the ‘obstacle’ fails to remain alive. To weasel his way around the law, he takes bets against the longevity of the ‘obstacle’ in the client’s way. In a seedy Birmingham office, disbarred lawyer Mr Bradley receives Osborne’s clients. In the TV series, she’s working for Osborne and fully aware of what’s going on. The book Jessie is at first unaware of the killings her questions help with, but starts to suspect and so is poisoned by Osborne to cover his tracks. In the TV series, he puts the Thallium in their water supply. He uses information gathered by a customer research company (for which Jessie Davis works) to ascertain which household and pharmaceutical products his victims use, and then enters their home under a handyman pretext and swaps their product for one laced with Thallium. Osborne’s murder methods differ slightly in the book.

Jessie Davis isn’t Osborne’s accomplice in the book # In the series, Jessie writes the list in her final hours, knowing that Osborne has poisoned her, and plans to take it to the police and confess, but Osborne – a retired chemist in the book, not the owner of a hardware and repairs shop – murders her in the street before she can do so. With huge plot spoilers for both, here’s how the Agatha Christie original differs from the TV drama… Sarah Phelps, whose most recent literary adaptation The Pale Horse, has just aired on BBC One, is one of the best boners around. To work as television, books require careful filleting – screenwriters to sweep their boning knife around the delicious flesh and discard the unappetising pale flab.

A novel’s worth of characters and sub-plots are too great for two hours of viewing. Gravity aside, page-to-screen adaptations demand change.

You can’t just put a book on the telly it’ll fall off.

The pale horse agatha christie book