Casualty has released a trailer for its new boxset ‘Internal Affairs’, which reveals a shock pregnancy and a dramatic ambulance crash in the ED.

After last week’s finale, the new run of episodes commence this Saturday (March 15), and will introduce viewers to new clinical lead Flynn Byron, played by Call the Midwife’s Olly Rix.

But before special forces medic Flynn takes the reins, he is brought into the hospital as a patient, and the trailer gives a first look at the serious accident he is involved in during the opening episode.

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Dylan reminds the new boss that the ED isn’t a warzone, to which Flynn responds: “Maybe it takes an outsider to see what needs to be done?” This tension looks set to continue as a later scene shows Flynn pinning his colleague against the wall in a rage.

Flynn also has a connection with surgeon Russell Whitelaw (played by Cold Feet’s Robert Bathurst), who reminds the newcomer: “I put my reputation on the line backing you for this job.”

Russell’s demanding approach in the operating theatre creates tension between Rida Amaan and Nicole Piper, who are both working on his team. But as Rida grows ruthless, she is left shaken by an event at work.

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There is also cause for celebration in Holby, as it seems that Iain Dean and Faith Cadogan’s wedding takes place during this series.

But the ED itself is under threat when an ambulance crashes directly into the hospital, leaving the team in grave danger.

Meanwhile, Stevie Nash is struggling in this new series following Rich Walker’s death, and she looks to be facing a new issue, as she is searched by the police in her house and believes that someone is targeting her.

But there is another big twist for Stevie, as a clip in the trailer shows her looking worried as she clutches a positive pregnancy test.

Elsewhere, Indie Jankowski reaches breaking point and is seen hurting an already injured patient. Who is this man, and does he have a connection to the student paramedic?