The symptoms are distressing; the diagnosis is a shock and the future a lingering, undignified and distressing death. How many of us would rather make a quick, painless exit? The vexed question of euthanasia is at the core of Mercy as Dr Collins , a country doctor married for thirty years helps his wife Margaret with a so-called assisted suicide. After suffering from what they assume to be a bout of flu, the Collins' world is turned upside down at the devastating news that Margaret Collins has been diagnosed with a rare degenerative brain disorder. With the only prospect being a long slow painful death, Margaret takes the decision to end her life, turning to her husband for his assistance. To the police, he is potentially a criminal. To the public and to the community that know him, Dr Collins is a hero. But what is the truth?

• Anthony Horowitz

• Art Malik
• James McAvoy
• Keeley Hawes