The hour-long episode will be filmed using a single camera all in one take to mark the special occasion.

To create this, the mobile camera covering A&E will be required to be cable free and will also have to cover action from inside a moving ambulance. The sound will be achieved with 40 hidden radio microphones and five boom operators, disguised as part of the set.

The episode will mostly focus on Duffy mentoring two teenage girls, Chloe and Diamond, who are being shown around the department for work experience, but will also include the series' regulars.

Cathy Shipton (who plays Nurse Lisa Duffin) said: "It is so exciting and nerve-wracking to be working on this episode and unlike anything any of us cast or crew have ever attempted before. It is a brilliant fly on the wall episode in real time, placing nurses central in the storyline. It will become a classic Casualty."

Erika Hossington, Series Producer for Casualty said: "It will be an intense, emotional hour where staff and patients are faced with life changing events. We want to reflect the front line in its unedited, rawest form, and this one shot episode with a brilliant script from Casualty creator Paul Unwin, has given us the opportunity to do that."

The special one-shot episode of Casualty will be broadcast this summer.