Here are the characters you need to meet – and the actors who play them...

Emilia Fox plays Dr Nikki Alexander

Who is Dr Nikki Alexander? Forensic Pathologist Dr Nikki Alexander has been a part of the team since her abrupt arrival in 2004. She is talented and tenacious, and a force to be reckoned with. This series she is trying to make a transatlantic relationship work with Matt Garcia (Michael Landes), who we met in the last series.

What else has Emilia Fox been in? Emilia Fox was born to a family of successful actors. She appeared in award-winning film The Pianist, and performed in many stage productions such as Rapture, Blister and Burn. More recently she's featured in BBC productions The Casual Vacancy, The Secrets, James Corden comedy The Wrong Mans, Sky drama Delicious, and John Simm's ITV thriller Strangers.

Richard Lintern plays Dr Thomas Chamberlain

Who is Dr Thomas Chamberlain? The Head of the Lyell Centre, the forensic science institute at the heart of Silent Witness. Thomas is cool and level-headed, and always thinks before he acts.

What else has Richard Lintern been in? Actor Richard Lintern appeared in period drama Spies of Warsaw alongside David Tennant. Before that he played a key role in cult BBC2 drama The Shadow Line. He also narrated the Bafta-winning documentary Between Life and Death, and, believe it or not, was the voice behind this David Beckham razor advert. The Crown fans might recognise him as the man who played Stephen Ward in the episode Mystery Man.

David Caves plays Dr Jack Hodgson

Who is Dr Jack Hodgson? The lead Forensic Scientist at the Lyell Centre, Jack is impulsive, clever and confident and the lead forensic scientist. When he isn’t solving impossible murder cases, Jack trains as a cage fighter.

David Caves says: "Jack has more carte blanche than perhaps the others do, as he is not attached to anyone. This gives him more freedom of movement, more potential for new relationships and a bit more mystery, which I think very important. We started a relationship with dad last year which develops more in this series. At heart, he’s still the lone-wolf he always was, but with very strong ties to Clarissa especially."

What else has David Caves been in? Since joining Silent Witness in 2013, David Caves has found time to appear in Ironclad 2 and in Royal Shakespeare Company's The Taming of The Shrew. He played Clint Hill in the Natalie Portman film Jackie.

Liz Carr plays Clarissa Mullery

Who is Clarissa Mullery? Clarissa is a witty, resourceful and efficient member of the team at the Lyell and has become Jack's right-hand woman.

Liz Carr says: "I like to think that Clarissa is the lynchpin of the Lyell Centre, in that we see her there a lot – she is a forensic examiner. She is incredibly smart; she doesn’t suffer fools gladly. She has a sense of humour. She has a unique relationship with Jack particularly. She entered the show because of Jack and they continue to be the closest of friends – in a very strong platonic relationship, which is rare these days."

What else has Liz Carr been in? Liz Carr is an actress, stand up comedian, broadcaster and disability rights activist, who has been a regular in Silent Witness since 2012. She presented the BBC Ouch! podcast for seven years until 2013, and fronted incisive BBC World Service documentary When Assisted Death Is Legal. You may recently have spotted her in Les Misérables, playing Fantine's concierge.

Episode 9 & 10 guest stars

Adelle Leonce plays DC Vail

Who is DC Vail? When a body is discovered floating in the Thames, DC Vail is convinced there is something strange about this death. She is an old friend of Jack's and shares his dogged determination to get to the truth.

What else has Adelle Leonce been in? After starring as Mary Mae in the TV series Shameless, she has appeared in shows including DCI Banks, Ordinary Lies, Strike, The Break, and Black Mirror – as Noni Harper-Brown in the episode Crocodile.

Ingrid Oliver plays DI Briggs

Who is DI Briggs? Detective Inspector Briggs is abrasive and angry, and is unconvinced the case is anything more than a suicide or an accident. She is also furious at the Lyell after an apparent mix-up in court, and is particularly angry about Dr Nikki Alexander's post-mortem report which seems to exonerate two men accused of killing a young police officer.

What else has Ingrid Oliver been in? Best-known for playing Petronella Osgood in Doctor Who, the actress's other credits include Watson & Oliver, The Increasingly Poor Decisions of Todd Margaret, and Angus Thongs and Perfect Snogging.

Dervla Kirwan plays Amanda Long

Who is Amanda Long? A pathologist at another forensics lab. When her post-mortem on a murdered police officer is dramatically different to Dr Nikki Alexander's, she accuses Nikki of making a serious mistake. She also has history with Dr Thomas Chamberlain.

What else has Dervla Kirwan been in? Most recently she starred as Megan Harris in John Simm drama Strangers (aka White Dragon). Dervla Kirwan played Miss Hartigan in the 2008 Doctor Who episode The Next Doctor, and has also appeared in Injustice, Strike Back, and Material Girl. And remember the old "this is not just food" M&S adverts? That was her providing the voiceover.

Kiran Sonia Sawar plays Alice

Who is Alice? A trainee at the Lyell Centre. You may have seen her in the background helping out for the last couple of episodes.

What else has Kiran Sonia Sawar been in? The young actress's star is on the rise. Kiran Sonia Sawar plays Shereen in Channel 4 comedy drama Pure, and has also recently appeared in Deep State, Brexit: The Uncivil War, Next of Kin, Black Mirror, The Boy with the Topknot, and Murdered by My Father.

Leemore Marrett Jr plays Jacob Nduka

Who is Jacob Nduka? A colleague of the dead man at Pujari pharmaceutical company. He and his colleagues live together in a house near the CEO's estate and are working on cutting-edge, highly-secret research.

What else has Leemore Marrett Jr been in? He currently stars in Death in Paradise as DS Florence Cassell's fiancé, Patrice Campbell. Leemore Marrett Jr has made appearances in Humans, Holby City, Call the Midwife and Vera, and he has already appeared in Silent Witness – playing DC Howard Stent.

Edward Franklin plays Richard Austin

Who is Richard Austin? Another of the dead man's colleagues and housemates.

What else has Edward Franklin been in? Edward Franklin played Louis Scatcherd in the TV series Doctor Thorne, and was posh art student Hugo in Informer.

Yennis Cheung plays Jenna Hong

Who is Jenna Hong? One of the dead man's colleagues and housemates. She is also dating Richard Austin.

What else has Yennis Cheung been in? The actress has taken on small roles in Strangers, Stan Lee's Lucky Man, Skyfall, Snatch, One Child and Chinese Burn. She played Janice in Chinese Girls in London, and Boamai in The English Class.

Art Malik plays Arthur Pujari

Who is Arthur Pujari? The incredibly wealthy boss of a pharmaceutical company. He lives in an impossibly large mansion and has a passion for gardening.

What else has Art Malik been in? The Jewel in the Crown star has recently appeared in a number of guest starring TV roles. He was Erasmus Nash in The Woman in White, Eddie Zubayr in Cold Feet, Alan Taheeri in Bancroft, Francesc Gacet in Borgia, Bunny Latif in Homeland, and Mr Amanjit Singh in Upstairs Downstairs, and even had a cameo in Doctor Who's The Ghost Monument. He also starred in Channel 4 period drama Indian Summers.

Anthony Taylor plays Leon Birchwood

Who is Leon Birchwood? A local man who was down by the river the night before the victim's body was discovered.

What else has Anthony Taylor been in? Aside from his theatre credits, Anthony Taylor has played minor roles in Patrick Melrose, Doctors, and He Kills Coppers. He is also featured in the music video for Stormzy's Gang Signs and Prayer.

Gregory Floy plays Judge Henderson

Who is Judge Henderson? The judge in a high-profile court case about the murder of a young officer, which hinges on whether he died from the wounds inflicted by the two defendants or whether the true cause of death was an undetected heart condition.

What else has Gregory Floy been in? Most recently, he played Bishop in the TV series Humans.

Golda Rosheuvel plays Barrister Lyndsey Morrison

Who is Lyndsey Morrison? The prosecution barrister, who attempts to discredit Nikki's evidence.

What else has Golda Rosheuvel been in? Starring alongside Florence Pugh, Golda Rosheuvel played Agnes in Lady Macbeth. Her other screen credits include minor roles in EastEnders, Torchwood, and Coronation Street, as well as a 2008 appearance in Silent Witness as a character called Celia Ojama.