BBC Casualty broadcasts first improvised episode

A special improvised episode of BBC medical drama Casualty is to be broadcast on Saturday.

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

It comes as ambulance crews and nurses prepare to go on strike later this month in disputes over pay.

Executive producer Jon Sen said he felt Casualty was at its best when it told stories that reflected the experiences of those working in the NHS.

He said: "We're in a constant dialogue with medical advisors and we were really aware of the changing pressures facing paramedics.

"And so we decided we wanted to focus on a story that was purely about them."

Casualty is the world's longest running medical drama, and it is the first time in its 36-year history that scripts have been ditched and every scene improvised.

He claimed improvising the show, filmed at the BBC's Roath Lock Studios in Cardiff, helped portray an "authentic experience".

"It allows the actors to really access their characters in a way that when you're very plot driven it never really does," he added.

The programme follows Holby City paramedics Jan, Sah, Teddy and Iain.

Michael Stevenson, who has played Iain since 2012, said the episode had a particular "realness".

"We met the guest actors in real time, in whatever situation they were in, which kept it fresh for us," he said.

Show advisor, paramedic Laura Johnson, was initially nervous about the premise, but said she came to think the idea was "genius".

"There were points in there where I laughed, there were points where the hairs on the back of my neck stood up and there was a point where I cried," she said.

You can see the special episode of Casualty at 20:10 GMT on BBC One and iPlayer