Downton Abbey and Slow Horses favourites to lead ITV drama from Unforgotten writer based on "extraordinary" true story

This article contains discussion of subjects including suicide that some readers may find upsetting.

ITV has announced the commission a new drama four-part drama series, Mavis Eccleston, which comes from Unforgotten and I, Jack Wright creator Chris Lang.

The series will star Downton Abbey's Penelope Wilton and Slow Horses star Jonathan Pryce as Mavis and Dennis Eccleston, respectively, and it will depict the tragic and extraordinary true story of the real-life couple's joint suicide pact.

Mavis and Dennis, who had been together for almost 60 year, decided to end their lives together when 81-year-old Dennis received a terminal cancer diagnosis and declined treatment, having had cancer twice before. Their decision caused anguish for their adult children, Kevin and Joy.

The synopsis for the series says: "Truly heartbreaking events unfold as the family desperately try to dissuade Dennis and Mavis from taking a lethal cocktail of medication, but they remain steadfast in their belief that they should leave the world together."

The synopsis continues: "Having taken an overdose together, they are both rushed to the hospital, where Dennis passes away, but Mavis survives. Following a confused and disorienting interview with hospital staff, the Police are alerted, and Mavis is arrested.

"In the midst of such tragedy, Mavis and her family, whilst trying to process the grief of having lost their father, now face the very real prospect of their mother spending the rest of her life in prison."

ITV has confirmed that Mavis Eccleston and her family have given their blessing to the drama, and have been available to Chris Lang and the production team throughout the script process.

The series was brought to production company Corestar Media by Grantchester star Tom Brittney, who has collaborated on the development of the series.

Brittney said in a statement: "When I first read about Mavis and Dennis in 2018, I was struck by the extraordinary love at its heart and the profound injustice their family endured.

"I felt their story, told with care and humanity, could be a powerful drama and a worthy contribution to a debate that remains urgent and deeply complex. Having worked with ITV, I knew they’d be the perfect home as an institution that champions powerful, social justice stories."

Meanwhile, Lang added: "From the moment Mavis and Dennis’s extraordinary story was told to me, I knew I had to write the script - but maybe not for the reasons one might suspect.

"Although their story does ask profound questions about how we live and end our lives, for me, their story was always about something simpler and more enduring. For me this was always about love. Unconditional love."

"Mavis was devoted to her husband, Dennis, their enduring love for each other clear to see to all," Wilton said. "They lived life on their own terms and when the time came, she wanted to respect his wishes.

"The fact she then faced the very real prospect of spending the rest of her life in prison for acting out of love is simply unimaginable. To be asked to bring her experience to life is a huge responsibility and true honour."

Pryce added: "This is a powerful and timely story of an extraordinary, devoted couple as they face the painful dilemma of assisted dying. We will hopefully honour their deep love for each other and their bravery."

Mavis Eccleston will begin filming in Bristol in June 2026, with news of further casting to be announced in due course.

For information and support, please visit Samaritans or SOS Silence of Suicide.

Mavis Eccleston will air on ITV1 and ITVX.

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