“I’m really proud of this episode,” Barney, who plays Cameron Mickelthwaite on the drama, said. “It’s special because we have intercut real-life stories from patients who have been affected by the kind of things we talk about in the show.

“It’s really great – Steve Hughes is a fantastic director. This episode is all about giving blood. Especially at Christmas time with heightened incidents, blood can get short in hospitals. We deal with that. I don’t want to spoil too much – you’ll see [what happens] on Saturday.”

Barney, who has also appeared alongside his father in Bradley Walsh & Son: Breaking Dad, paid tribute to the various advisors on the soap, sharing that the cast and crew wanted to be “true to the NHS”.

“We work very closely with the medical advisors, and they’re all fantastic at what they do,” he said. “They show us the ropes and help us through tough scenes. I’ve had days where I’ve learned how to suture [or] do CPR. We want to be as true to the NHS because they are so great.”

Much like the special which celebrated the 75th anniversary of the NHS, the festive special will include real-life testimonies from contributors who have been directly impacted by UK blood donation as well as interviews with key workers who help run the country’s blood service.

Casualty airs on Saturday nights on BBC One and now streams first on BBC iPlayer, where episodes are released at 6am on the day of transmission. The One Show airs on weekdays at 7pm on BBC One.

Read more Casualty spoilers on our dedicated homepage

“It’s really great.” Casualty star Barney Walsh has spoken about the upcoming Christmas special, describing himself as “really proud” of the episode. The festive episode, which is titled ‘All I Want for Christmas’, is due to air on Saturday (December 21), with the action following various characters as the Emergency Department struggles with a shortage of blood.…