The star, who played Charlie Fairhead in the BBC One medical drama, is its longest-serving cast member.

Expletives were mistakenly shown before the watershed although the words were not audible on screen.

The instalment, called Thin Green Line, focuses on real-life pressures facing paramedics.

The episode will be unscripted to reflect the stresses and strains facing health staff.

Viewers will see characters pop up in other soaps, with a Hollyoaks actor appearing in EastEnders.

A campaigner who has helped raise awareness of the issue helps scriptwriters on the topic.