Is ITV’s The Party based on a book? Elizabeth Day’s novel and the Martin and Ben secret explained

ITV's The Party began on Sunday 11 October, and plenty of viewers who settled in for the opening episode will have wondered whether the story of Martin Gilmour and Ben Fitzmaurice started life somewhere else. It did.

The five-part psychological thriller is adapted from Elizabeth Day's 2017 novel of the same name, and the friendship at its centre, along with everything the two men have kept hidden, comes straight from the book.

How Luke Evans brought the novel to ITV

The journey to the screen began with Luke Evans, who plays Martin. He read the novel and took it to World Productions, the company behind the series, and he is also an executive producer. "From the moment I read Elizabeth Day's novel, I knew it had the makings of something truly special for television," he said when ITV announced the drama. Day, who is an executive producer too, said she was "incredibly grateful to the brilliant Luke Evans for championing my book in the first place". The scripts are by Sarah Solemani, who adapted the novel and also appears as Lucy, Martin's pregnant wife.

What happens in The Party

Both the book and the series follow Martin, who is raised by his working-class mother, Sylvia, and wins a scholarship to an elite boarding school. It is there that he meets Ben, the son of a wealthy family, and the bond they form goes on to shape Martin's whole adult life. Ben's parents, Lady Katherine and Lord George Fitzmaurice, give him a sense of belonging he has never quite found elsewhere, and he stays loyal to Ben through every crisis that follows.

Three decades later, Martin is working as a journalist when he is invited to Ben's lavish birthday party at Denby Hall, the Fitzmaurice country estate. Ben has become a politician and is weighing up a bid for the leadership of the Conservative Party, a prospect that leaves Martin deeply uneasy. Before the night is out, a shocking event at the party leads to a police investigation, and from then on the drama moves between the present day and the men's years at school, at university and on the London party scene.

What is the secret between Martin and Ben?

That leaves the question of the secret. ITV's own description of the series says Martin fears the publicity Ben's bid would bring, "dredging up the secrets of their past with tragic consequences". The opening episode sets up Martin as the keeper of Ben's darkest secrets, and makes it plain that something from their shared history could threaten both Ben's ambitions and the friendship itself. What that is, and what really happened at Denby Hall, is the mystery the whole series is built on, so we are not going to give it away here. Readers of the novel will already know where the story goes, which is worth bearing in mind for anyone watching week by week and tempted to look it up.

Evans has called the drama "a gripping exploration of loyalty, class, and the truths we hide", and the gap between Martin's background and the world he works so hard to fit into is never far from the surface. He talked about why the role felt so personal to him in our interview ahead of the launch, which is well worth a read alongside the series.

Tom Cullen plays Ben, with Joanna Scanlan as Sylvia, Lydia Leonard as Ben's wife Serena, and Lindsay Duncan and Douglas Hodge as Lady Katherine and Lord George. Viviane Andereggen directs, and the series was filmed in Wales, including in Cardiff, in October 2025.

The Party continues on ITV1, and all five episodes are already available on ITVX for anyone who would rather not wait. Whether you come to it fresh or know the novel well, the weeks ahead will show how closely Solemani's version stays with Day's book as Martin's loyalty to Ben is put to the test.

Images: ITV.