What else has Johann Myers been in? The actor and director has recently appeared in Idris Elba's movie Yardie, and in the TV series Snatch, Guerrilla, and In the Dark.

Heather Peace plays DI Carey Murphy

Who is DI Carey Murphy? DCI Cramer's second-in-command on this investigation.

What else has Heather Peace been in? The actress, musician and LGBT rights activist is perhaps best known for her roles as Nikki Boston in Waterloo Road, Sally 'Gracie' Fields in London's Burning, Fiona Murray in Kay Mellor's drama The Chase, or Sam Murray in Lip Service.

Andrew Knott plays Nick Marlow

Who is Nick Marlow? When we meet Nick, we only know that this character – who works in the armed forces – is recently separated from wife Amy and their young children. She is furious at her husband and deeply upset – but why?

What else has Andrew Knott been in? Back in the day, he starred as Dickon in the 1993 movie The Secret Garden. More recent roles have included Joshua in My Cousin Rachel, Vince Callaghan in Casualty, DS Lee Miekel in Black Work, and Sam Milburn in Grantchester.

Jemima Rooper plays Amy Marlow

Who is Amy Marlow? Nick's wife. She is struggling to deal with the recent upheaval in her life.

What else has Jemima Rooper been in? The actress first came to fame when she played George in the Enid Blyton TV series The Famous Five. She has since starred in The Black Dahlia, Lost in Austen, the plays Her Naked Skin, Me and My Girl, and One Man Two Guvnors. Recent credits have included Trauma, Fearless, and Death in Paradise.

Emma Frankland plays Kelly Hayes

Who is Kelly Hayes? A trans activist who works at a helpline for trans people or those questioning their gender identity.

What else has Emma Frankland been in? The actress is co-creator of the theatre company None of Us is Yet a Robot. One of her live performances has been made into a short film titled Rituals for Change – but this role in Silent Witness is her first TV appearance.

Nicole Gibson plays Evie Williams

Who is Evie Williams? The boss (or "big cheese") at the helpline, which is called Transaction. Evie is dedicated to her job and proud of her team.

What else has Nicole Gibson been in? She played Georgia in Catastrophe back in 2015, and has also appeared in the TV series Borderline.

Paul Tylak plays David Stein

Who is David Stein? A friend of Transaction. He works in the political world and helps the cause.

What else has Paul Tylak been in? The Irish actor, writer and comedian recently starred as Raza's drunken but well-meaning dad Hanif Shar in the BBC drama Informer. He is also an accomplished voice actor, with credits including Ballybraddan, Zig and Zag, Chloe's Closet, and All Creatures Big and Small.

Raymond Waring plays Toby Logan

Who is Toby Logan? One of the volunteers at the helpline.

What else has Raymond Waring been in? He played Daniel in the TV series Knightfall, and has also appeared in The Head Hunter, Ripper Street, and America's War on Drugs.

Olivia Chenery plays Beth Roscoe

Who is Beth Roscoe? Someone from Kelly's past.

What else has Olivia Chenery been in? She played Mary Stuart in the TV series Queens, and is also known for her role in Penny Dreadful.

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Sian Webber and Andrew Neil play Evie's parents

Who are Maeve and Reece Williams? Evie's mum and dad.

What else has Sian Webber been in? You're most likely to recognise her as Ritchie Scott from EastEnders. Back in the 80s she starred in Howards' Way, playing Emma Neesome.

What else has Andrew Neil been in? He played Mr Salthouse in the 2018 series of Unforgotten, and has also made brief appearances in Victoria, Edge of Tomorrow, and Humans.

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