[13] Belinda Campbell, who executively produced the drama between 2007 and 2011, thought that webisodes would be a "new [way] to add value for our loyal fans", something which the team constantly look to do.

Other webisodes are designed to help progress storylines on the main show: "Short Story" explores Ruth Winters' (Georgia Taylor) stay at the hospital's psychiatric ward; "Mistletoe and Rum" follows the secret relationship between Tess Bateman (Suzanne Packer) and Adrian "Fletch" Fletcher (Alex Walkinshaw); "Nurse Factor" supports the introduction of four new student nurse characters; "Gone in Sixty Seconds" gives an insight into a bus crash; "Mrs Walker-To-Be" explores the night before Zoe Hanna (Sunetra Sarker) and Max Walker's (Jamie Davis) wedding; and "On Call" starts a storyline featuring Caleb Knight (Richard Winsor) being told he has a daughter.

Some webisodes have been standalone and not followed in the main show: "The Kids Aren't Alright" focuses on Jeff Collier's (Matt Bardock) estrangement from his children; "The Spirit of Christmas" and "The First Noel" are Christmas specials; and "Radio Holby" sees Noel Garcia (Tony Marshall) become the hospital's radio DJ.

[30] As Polly Emmerson (Sophia Di Martino) continues to be stalked by homeless man Alistair (Joe McFadden), the webisode follows the events between the series 24 episodes "Regrets" and "Every Breath You Take".

[13][30] Executive producer Belinda Campbell praised Di Martino, McFadden and Roden, and described the webisode as "a really special viewing opportunity for die-hard Casualty lovers".

[13] "Short Story" is a two-part webisode focusing on Ruth Winters' (Georgia Taylor) stay at the hospital's psychiatric ward.

[31] Part 2 of the webisode follows Ruth as she struggles to adapt to her new environment and meets Carl, a man who is billed as "a mysterious stranger on the Psychiatric Ward" by a BBC Online contributor.

[19] The webisode was announced on 28 March 2012, and follows Sam's experience as a medic at Camp Bastion in Afghanistan before she joined Holby City Hospital.

[19] Producers created the special episode so they could "explain Sam's brusque bedside manner and brave but impulsive decision-making".

[33] Executive producer Johnathan Young wanted to explore the backstory and actions of Sam, whom he described as "one of [the show's] most colourful characters", and felt that the webisode would be beneficial in doing so.

[20] "Mistletoe and Rum" is a webisode focusing on the relationship between nurses Tess Bateman (Suzanne Packer) and Adrian "Fletch" Fletcher (Alex Walkinshaw), which was released on 15 December 2012.

[22] "Gone in Sixty Seconds" is a webisode featuring paramedics Jeff Collier (Bardock) and Kathleen "Dixie" Dixon (Hazlegrove) arriving at the site of a coach crash.

[35] "Scars and Nightmares" is a webisode marking Remembrance Day and focusing on the backstory of Iain Dean (Stevenson), which was released on 2 November 2013.

[23] The special was announced on 1 November, and sees Iain and Sam Nicholls (Salt) visit former colleague Kenny in a PTSD rehabilitation centre.

[23] Executive producer Oliver Kent wanted to explore the backstory and relationship shared between Iain and Sam, and thought that the special was "a great opportunity" to do that and provide the audience with "something extra".

[23] "The Spirit of Christmas" is a Christmas-themed webisode focusing on Big Mac (Charles Dale) and Noel Garcia (Tony Marshall) as they solve a festive mystery after a night of drinking.

[25] The special sees Noel try to boost team morale following the death of Jeff Collier (Bardock) by becoming the hospital DJ, a dream he has wanted to achieve.

[25] Series producer Erika Hossington expressed her delight at the webisode being commissioned and praised the team, who described as "some fantastic talent", and their "passion, enthusiasm and dedication".

"[25] "Mrs Walker-To-Be" is a webisode released on 22 August 2015, focusing on Zoe Hanna (Sarker) and Max Walker (Jamie Davis) on the night before their wedding.

[26] "On Call" is a webisode focusing on Caleb Knight (Richard Winsor) as his former girlfriend Taylor Ashbie (Sarah Jayne Dunn) returns and introduces him to his daughter.

[37] It focuses on Noel finding where the staff Christmas party is being held, and features cast members dressed as Pantomime characters.

[14] Jay Faldren (Ben Turner) is sceptical of the ward and helps Pudsey Bear's health by raising money for the charity.

[14] To celebrate 25 years of BBC soap opera EastEnders, five members of the Casualty cast filmed a special to congratulate them.

[15] Michael French, who appears in Casualty as Nick Jordan, stars in the special and gives a nod to his EastEnders character, David Wicks, in a scene.

[15] In an episode of children's television show Blue Peter, first broadcast on 10 March 2010, presenter Joel Defries visits the set of Casualty.

[28] Back to Ours, a concept based on Gogglebox and first adopted by EastEnders, features actors Derek Thompson (Charlie Fairhead) and Cathy Shipton (Lisa "Duffy" Duffin) watching a selection of their "most memorable scenes".

[28] In the special, the actors discuss Casualty being debated in the House of Commons as well as Hollywood actress Kate Winslet's guest appearance in 1993.