Bad Sister’s Sharon Horgan and Good Omen’s Michael Sheen star as a married couple going through an emotional legal battle.

The trailer shows Nicci (Horgan) and Andrew (Sheen) finding out that the condition of their daughter Marnie, who suffers with a rare neuro-muscular disorder, is rapidly declining.

When doctors tell the couple it is in Marnie’s best interests to cease all treatments, Nicci and Andrew enter a legal battle to go against the doctor’s wishes and fight for their daughter’s life.

Joining Horgan and Sheen are Niamh Moriarty (Jack Thorne’s A Christmas Carol) and Alison Oliver (Conversation with Friends) as their daughters Marnie and Katie.

The ensemble cast includes Noma Dumezweni (The Undoing), Chizzy Akudolu (Sorry, I Didn’t Know), Des McAleer (Hope Street), Mat Fraser (His Dark Materials), Gary Beadle (Grantchester), Jack Morris (Strike), Pippa Haywood (Bodyguard), Shane Zaza (Happy Valley), Lucian Msamati (Gangs of London), and Lisa McGrillis (Mum).

Two-time RTS Award winner Lenny Rush (Am I Being Unreasonable?) announced via his Instagram that he will also appear in a small role in the series.

Jack Thorne says: "As a parent of a three-year-old I've looked at the cases in the media about 'best interests' with some fascination and a little dread, when the worst happens, how do you keep your head when everything around you feels wrong? We are going to try and tell a nuanced story that talks about this issue from all sides.”

Best Interests premieres on BBC One and iPlayer on Monday 12 June.